The outbound glossary

Also called Split Testing

A/B testing compares two versions of a message, page or sequence against a single metric to establish which performs better.

A valid test changes one variable, splits the audience randomly, and runs until the result is statistically meaningful, which in cold outreach usually means a larger sample than people expect, often thousands per arm for a small effect. Testing subject lines against open rate is now unreliable given privacy proxies, so reply rate is the sounder target. The bigger wins almost always come from testing the offer or the segment rather than the wording.

See also Open Rate, Reply Rate, Conversion Rate, Personalization

Also called ABM

Account-based marketing is a B2B strategy that treats a defined list of high-value accounts as individual markets, coordinating sales and marketing effort against each one.

ABM inverts the usual funnel: instead of generating volume and filtering down, you pick the accounts first and work them deliberately. It suits high contract values and long buying cycles, where a handful of accounts represent most of the revenue and several people inside each must be convinced. It depends on multi-threading and on genuine account research, so it does not scale the way broad outbound does. Attempting ABM across a thousand accounts usually produces neither ABM nor good outbound.

See also Multi-Threading, ICP, Buyer Intent, Prospecting

Also called DNSBL, Blacklist

A blocklist is a published database of IP addresses and domains known for sending spam, which receiving servers consult before accepting mail.

Receiving servers query blocklists in real time and may reject or filter anything listed. Spamhaus is the most consequential; others carry less weight but still cost you placement. Listings are usually triggered by hitting spam traps, a spike in complaints, or sending from a compromised server. Most operate a delisting request process, but repeat listings are progressively harder to clear. Check your sending domain and IP against the major lists before you start a campaign, not after open rates collapse.

See also Spam Trap, Sender Reputation, Deliverability

Bounce rate is the percentage of sent emails that the receiving server refuses to deliver.

Bounce rate is the clearest read on list quality, and inbox providers use it the same way. Above roughly 2–3% you are signalling that you did not verify your list, and reputation damage follows quickly; under 2% is the working target, and a verified list should come in well below 1%. The figure matters more at the start of a campaign than the end, because providers weight early signals heavily. Verification before sending is the only reliable way to control it.

See also Hard Bounce, Soft Bounce, Email Verification, Sender Reputation

Also called Intent Data

Buyer intent is a signal suggesting an account is actively moving toward a purchase, such as hiring for a relevant role, raising funding, or researching a category.

Intent signals are either first-party (someone visited your pricing page, opened three emails, started a trial) or third-party, inferred from behaviour elsewhere such as content consumption or review-site activity. First-party signals are far more reliable; third-party data is directional at best and frequently oversold. The practical value of intent is timing rather than targeting: it rarely tells you who to contact, but it can tell you when a company you had already qualified is worth contacting now.

See also Technographics, Account-Based Marketing, Lead Scoring, Newly Registered Domain

CAN-SPAM is the United States law governing commercial email, which permits unsolicited messages provided the sender follows its rules on honesty and opt-out.

CAN-SPAM does not require prior consent, which is why US cold email is lawful. It does require accurate From and Reply-To headers, a non-deceptive subject line, identification of the message as an advertisement where applicable, a valid physical postal address, and a working opt-out honoured within ten business days. Penalties are assessed per message and are substantial. Note that it pre-empts state law only partially, and that other jurisdictions your recipients live in may apply stricter rules regardless.

See also GDPR, Cold Email, Unsubscribe, Opt-In

Also called Accept-All

A catch-all domain is one configured to accept mail sent to any address at that domain, whether or not the mailbox actually exists.

Because the server accepts everything, SMTP verification cannot tell you whether a specific mailbox is real, so verifiers return catch-all or accept-all rather than valid or invalid. These addresses are a genuine judgement call: some will land, some will bounce later, and mailing them in bulk is how bounce rates creep up. The usual approach is to segment them, send to them separately from your confirmed addresses, and keep the volume low enough that the bounces they produce do not contaminate the main campaign.

See also Email Verification, Bounce Rate, MX Record

Also called CTR

Click-through rate is the percentage of delivered emails in which the recipient clicked at least one link.

CTR is a better engagement signal than opens because it requires a deliberate action, though link-scanning by security gateways produces some phantom clicks in enterprise segments. In cold outreach, links are a mixed blessing: they add tracking but also add a spam signal, especially shortened or mismatched ones. Many teams keep the first message link-free precisely to protect deliverability, and introduce links only once a reply has established the thread.

See also Open Rate, Reply Rate, Conversion Rate, Deliverability

A cold email is an unsolicited message sent to someone with no prior relationship to your company, for a business purpose.

Cold email is legal in most jurisdictions when done correctly, but the rules differ sharply: CAN-SPAM in the United States permits it with honest headers and a working unsubscribe, while GDPR in the EU requires a lawful basis and, in several member states, prior consent for electronic marketing. Effective cold email is short, specific to the recipient's situation, and asks for something small. The failure mode is treating it as a volume exercise, which produces complaints, blocklistings and no pipeline.

• Cold email tooling

See also Cold Outreach Sequence, CAN-SPAM, GDPR, Personalization, Deliverability

Also called Cadence, Drip Sequence

A sequence is a scheduled series of outreach steps (emails, calls and social touches) sent to a prospect over a set period until they reply or the sequence ends.

A sequence is defined by its steps, the delay between them, and its exit conditions. Most replies arrive after the first message, which is the entire argument for following up, but the returns fall away quickly and a sequence that runs too long converts interest into irritation. Four to six touches over two to three weeks is a common shape. The single most important setting is the exit condition: a sequence that keeps sending after someone has replied is worse than no sequence at all.

• Sequences in Aries Leads

See also Follow-Up, Cold Email, Outreach, Reply Rate

Company enrichment adds organisation-level detail to a record: industry, headcount, revenue band, location, funding and the technologies the company runs.

Company fields are what an ideal customer profile is actually built from, and they are how a list gets segmented before anyone writes a word of copy. They are also more stable than contact fields: a company's industry rarely changes, while its staff turn over constantly. Where a record has a company domain but nothing else, company enrichment is usually the first pass, because it determines whether the account is worth spending contact-level credits on at all.

See also Data Enrichment, Contact Enrichment, Firmographics, ICP

Contact enrichment adds person-level detail to a record: full name, job title, seniority, department, direct phone number and social profiles.

Contact-level fields drive who you talk to and how. Seniority decides whether a message is framed around a day-to-day problem or a budget one; department decides which problem is even relevant. Contact data decays faster than company data because people change jobs. The commonly cited figure is around 30% of B2B contact records going stale each year, so contact enrichment is a recurring process rather than a one-off import.

See also Data Enrichment, Company Enrichment, Data Decay, ICP

Conversion rate is the percentage of people at one stage of a funnel who progress to the next.

Conversion rate is meaningless without naming both stages, which is the most common reporting error in this area. A quoted 3% could be anything. In outbound the useful chain is delivered to replied, replied to meeting booked, meeting to opportunity, opportunity to closed. Measuring each transition separately tells you where the problem actually is: a strong reply rate with weak meeting conversion is a qualification problem, not a copy problem.

See also Reply Rate, Cost Per Lead, MQL and SQL

Also called CPL

Cost per lead is the total spend of a campaign or channel divided by the number of leads it produced.

An honest CPL includes tooling, data, and the loaded cost of the people doing the work, not just advertising spend. Outbound programmes routinely under-count by omitting salaries. It is most useful compared across channels and over time, and least useful as an absolute benchmark, since it varies enormously by market and contract value. A low CPL producing leads that never convert is worse than a high one that does, which is why it should always be read alongside conversion rate.

See also Conversion Rate, Lead Generation, Lead

Also called Customer Relationship Management

A CRM is the system of record for a company's contacts, accounts, deals and the history of interactions with each.

The CRM is where outbound work is supposed to land, and the quality of that landing decides whether the effort compounds or evaporates. Sequences and enrichment tools that write back automatically keep the record current; ones that require manual entry produce a CRM that is confidently wrong. The usual integration points are creating or updating a contact when it is enriched, and firing an event when someone opens, clicks, replies or converts.

• Webhooks and CRM events

See also Data Enrichment, Lead Scoring, MQL and SQL

Also called Comma-Separated Values

CSV is a plain-text file format in which each line is a record and fields are separated by commas, used as the common exchange format for contact lists.

CSV is universal and therefore unavoidable, but it carries no types, no encoding guarantee and no schema, which is where most import problems originate: leading zeros stripped from phone numbers, names mangled by the wrong encoding, and commas inside fields breaking rows. Exporting as UTF-8 with quoted fields avoids most of it. The deeper point is that every CSV hop between tools is a chance for data to degrade, which is the practical argument for keeping the workflow in one system.

See also Data Enrichment, List Building, CRM

Data decay is the rate at which the records in a database stop being accurate, chiefly because people change roles and companies change shape.

B2B contact data is widely reckoned to decay at roughly 2–2.5% a month, or around 30% a year, driven by job changes, restructures, acquisitions and domain migrations. The practical consequence is that a list is a perishable asset, not a permanent one: a database imported two years ago and never touched is mostly fiction. Decay is why verification is run immediately before a send rather than at import, and why re-enrichment belongs on a schedule.

See also Data Enrichment, Lead List Hygiene, Email Verification, Spam Trap

Data enrichment is the process of adding missing fields to records you already hold, so a bare email address becomes a contact you can segment and personalise against.

An email address on its own supports exactly one message, written for everybody. Enrichment attaches job title, seniority, company size, industry, location, technology stack and direct dials, and those fields are what make segmentation possible. Segmentation in turn is what separates a sequence that gets replies from one that gets complaints. Enrichment is also the cheapest way to improve a list you already own: upgrading old records usually costs less than sourcing new ones and produces better response, because the accounts are already qualified.

• Enrichment in Aries Leads

See also Contact Enrichment, Company Enrichment, Waterfall Enrichment, Firmographics, Data Decay

Deliverability is the measure of whether the email you send actually arrives in the recipient's inbox rather than the spam folder or nowhere at all.

Deliverability is distinct from delivery. A message can be accepted by the receiving server (delivered) and still be filed in spam, which means it was delivered but not placed. Deliverability is decided by a mix of authentication (SPF, DKIM, DMARC), the reputation of your sending domain and IP, how recipients react to what you send, and the technical hygiene of your list. It is the single constraint most outbound programmes underinvest in: a list of ten thousand people is worth nothing if the sending domain has been filtered.

• Email warm-up in Aries Leads

See also Inbox Placement, Sender Reputation, SPF, DKIM, DMARC, Email Warm-up

Also called Temporary Email, Burner Address

A disposable email address is a short-lived mailbox from a throwaway provider, created to receive a signup confirmation and then abandoned.

Disposable addresses are used to claim free trials, bypass gated content, and evade signup limits. In a lead list they are worthless; in your own product they are worse, because they inflate signup numbers, distort activation metrics and are a common vector for abuse. Blocking them is best done at the point of entry, with an API check on the registration form, rather than cleaning them out of your database afterwards. The provider domains change constantly, so the check needs a maintained list rather than a static one.

• Fake email prevention API

See also Email Verification, Role-Based Email

Also called DomainKeys Identified Mail

DKIM attaches a cryptographic signature to outgoing email so the receiving server can verify the message genuinely came from your domain and was not altered in transit.

Your sending server signs each message with a private key; the matching public key sits in a DNS record at your domain. The recipient fetches the key, verifies the signature, and knows both the sender and that the headers and body were not tampered with. Unlike SPF, DKIM survives forwarding, which makes it the stronger of the two. Keys should be at least 1024-bit (2048 is now standard) and rotated periodically. A missing or failing DKIM signature is one of the fastest routes to the spam folder.

See also SPF, DMARC, Deliverability

Also called Domain-based Message Authentication, Reporting and Conformance

DMARC is a DNS policy that tells receiving servers what to do with email claiming to be from your domain that fails SPF and DKIM checks.

DMARC sits on top of SPF and DKIM and adds two things: alignment, which requires the authenticated domain to match the one the recipient actually sees, and a policy telling receivers whether to take no action, quarantine, or reject failures. It also sends you aggregate reports on who is sending as you. Since 2024, Google and Yahoo have required a DMARC record from anyone sending bulk mail to their users, which moved it from good practice to a precondition. Start at none, read the reports, then tighten to quarantine and reject.

See also SPF, DKIM, Sender Reputation, Deliverability

Domain reputation is the portion of sender reputation tied to your sending domain rather than the IP address the mail leaves from.

Domain reputation follows you across infrastructure. Change sending provider and your IP reputation resets, but the domain's history does not, which is why it is the more durable of the two signals and the one providers increasingly weight. A new domain has no reputation at all, which is its own problem. Providers treat unknown senders with suspicion, so volume has to be ramped rather than switched on. Most teams that send cold email register a separate domain, or a subdomain, specifically so a mistake cannot damage the primary one.

See also Sender Reputation, Email Warm-up, Newly Registered Domain, DMARC

Also called Confirmed Opt-In

Double opt-in requires a person to confirm their subscription by clicking a link in a verification email before they are added to your list.

The second step proves the address is real and that the person actually controls it, which eliminates typos, malicious signups and a category of spam trap in one move. It reduces raw list growth and improves almost everything else: deliverability, engagement rates, and the evidentiary quality of your consent record. For any list you intend to mail repeatedly, the smaller confirmed list outperforms the larger unconfirmed one.

See also Opt-In, Email Verification, Spam Trap, GDPR

Throttling is the deliberate limiting of how many messages you send per mailbox per hour or day, to stay within what inbox providers consider normal human behaviour.

Providers rate-limit inbound mail from any one sender, and exceeding the limit produces deferrals rather than outright rejection: your messages queue and arrive late, or not at all. Sensible practice is well under a hundred cold messages per mailbox per day with randomised intervals, spread across several mailboxes rather than pushed through one. Throttling also protects you from your own mistakes: a bad list sent slowly produces a warning signal you can react to, where the same list sent at once produces a blocklisting.

See also Email Warm-up, Deliverability, Sender Reputation

Also called Email Validation

Email verification is the process of checking that an address is correctly formed, that its domain can receive mail, and that the specific mailbox exists, before you send to it.

Verification runs in layers: syntax, then whether the domain has a valid MX record, then an SMTP conversation with the receiving server to test whether the individual mailbox is accepted. Good verifiers also flag disposable domains, role accounts and catch-all domains, where the mailbox cannot be confirmed either way. It is the single highest-return step in outbound. It costs a fraction of a cent per address and protects the sending domain that your entire programme depends on.

• Verification in Aries Leads

See also Bounce Rate, Catch-All Domain, Disposable Email, Role-Based Email, MX Record

Email warm-up is the practice of gradually increasing send volume from a new domain or mailbox while generating positive engagement, so inbox providers learn to trust it.

A brand new sending domain has no history, and providers treat sudden volume from an unknown sender as the signature of a spammer. Warm-up starts at a handful of messages a day and ramps over several weeks, usually through a network that opens, replies to and moves messages out of spam, building the engagement pattern of a legitimate correspondent. Expect four to eight weeks before a new domain is ready for real campaign volume. Skipping this step is the most common reason a first campaign lands entirely in spam.

• Warm-up included in Aries Leads

See also Domain Reputation, Sender Reputation, Deliverability, Email Throttling

Firmographics are the descriptive attributes of a company (industry, headcount, revenue, ownership structure, location and age) used to segment B2B markets.

Firmographics are to B2B what demographics are to consumer marketing: the baseline segmentation layer. They answer whether an account belongs in your market at all, which is a different and prior question to whether a particular person is worth contacting. Most ideal customer profiles are defined almost entirely in firmographic terms, and most wasted outbound spend comes from lists that were never filtered against one.

See also Technographics, ICP, Company Enrichment, TAM

A follow-up is a subsequent message sent after an initial outreach attempt that received no response.

Follow-ups exist because attention is a lottery: the first message often arrives at a bad moment rather than being rejected. The useful follow-up adds something: a different angle, a relevant example, a shorter ask. The useless one says only that you are following up, which asks the recipient to do the work of remembering why they should care. Diminishing returns set in quickly, and each additional unanswered touch raises the chance of a complaint rather than a reply.

See also Cold Outreach Sequence, Reply Rate, Spam Complaint

Also called General Data Protection Regulation

GDPR is the European Union regulation governing the processing of personal data, which applies to anyone handling data about people in the EU regardless of where the sender is based.

Under GDPR a business email address identifying a named person is personal data, so holding and mailing it needs a lawful basis. For B2B outreach that is usually legitimate interest, which requires a documented balancing assessment rather than an assumption. Separately, the ePrivacy rules on electronic marketing vary by member state, and several require prior consent even B2B. Practical obligations include telling people where their data came from, honouring erasure and objection requests, and keeping records. Penalties reach 4% of global turnover.

See also CAN-SPAM, Opt-In, Cold Email, Unsubscribe

A hard bounce is a permanent delivery failure, usually because the address does not exist or the domain cannot receive mail.

Hard bounces are final and must be removed from your list immediately. Continuing to send to them is exactly the pattern providers use to identify senders working from purchased or scraped data. Common causes are a mistyped address, an employee who has left, or a domain that no longer has an MX record. Because hard bounces are permanent, they are entirely preventable through verification, which is why a high hard bounce rate reads as negligence rather than bad luck.

See also Soft Bounce, Bounce Rate, Email Verification, MX Record

Also called Ideal Customer Profile

An ideal customer profile is a written description of the type of company that gets the most value from your product and is therefore worth targeting.

An ICP describes companies, not individuals. Describing an individual is a buyer persona, which is a separate document. A useful one is built from your existing best customers rather than aspiration, and is specific enough to exclude: industry, headcount band, revenue band, geography, technology stack, and the situation that creates the need. The test of an ICP is whether two people on the team would classify the same account the same way. If not, it is a slogan rather than a profile.

See also Firmographics, Technographics, Prospecting, TAM, Lead Scoring

Inbox placement is the share of your delivered email that lands in the primary inbox rather than spam, promotions or another filtered folder.

Inbox placement is the metric that matters, and it is not the same as the delivery rate your sending tool reports. A provider will usually accept a message and then decide where to file it, so you can show a 99% delivery rate while most of the send sits in spam. Placement is measured with seed lists (addresses you control at each major provider) or with a dedicated monitoring service. If open rates fall sharply without a corresponding change in your copy or list, placement is the first thing to check.

See also Deliverability, Sender Reputation, Open Rate, Spam Trap

A lead is a person or company that has been identified as a potential customer, whether or not they have expressed any interest yet.

The word is used loosely enough to cause real confusion between teams. Marketing often calls anyone who filled in a form a lead; sales often reserves the word for someone who has shown genuine buying interest. The gap between those two definitions is where most pipeline arguments start, which is why MQL and SQL exist as explicit stages. Agreeing what qualifies as a lead, and writing it down, is usually worth more than any tooling change.

See also MQL and SQL, Lead Generation, Lead Scoring, Prospecting

Lead generation is the process of identifying potential customers and creating the contact that starts a sales conversation.

It splits into inbound, where people find you through content, search or referral, and outbound, where you identify accounts and approach them directly. The two behave differently: inbound is slower to build, compounds over time and produces warmer conversations; outbound is faster to start, more controllable and more dependent on data quality. Most B2B teams run both, and the tooling overlaps more than the strategies do: the same verified contact record serves either motion.

• The Aries Leads platform

See also Prospecting, Outreach, Cold Email, Lead, Cost Per Lead

List hygiene is the ongoing work of keeping a contact list accurate: removing bounces and unsubscribes, suppressing non-responders, de-duplicating, and re-verifying before each send.

Hygiene is what stops a list quietly turning into a liability. The routine is unglamorous: suppress hard bounces immediately, honour unsubscribes permanently, drop contacts who have not engaged across several campaigns, de-duplicate across sources, and re-verify shortly before sending rather than relying on a check run months ago. Neglected lists accumulate recycled spam traps, which is the specific failure that turns a deliverability problem into a blocklisting.

See also Data Decay, Spam Trap, Bounce Rate, Email Verification, Unsubscribe Rate

Lead scoring assigns a numeric value to each lead based on how well they fit your profile and how they have engaged, so sales can work the list in order.

A score normally combines two independent things: fit, drawn from firmographic and technographic data, and engagement, drawn from behaviour such as opens, clicks, replies and site visits. Keeping them as two dimensions is more useful than one blended number, because a high-fit account with no engagement needs a different action from a high-engagement lead who will never buy. Scores drift as the business changes, so a model that is never recalibrated eventually ranks on the wrong things.

See also MQL and SQL, Buyer Intent, ICP, Firmographics

List building is the practical assembly of a contact list: sourcing records, filtering them against your profile, finding and verifying addresses, and enriching the fields you will personalise on.

A usable list is not a spreadsheet of email addresses. It is a set of records where every row has been checked against your ideal customer profile, verified as deliverable, and enriched with the fields your copy actually references. Building it from several sources (social profiles, domain lists, public directories, the daily domain register) produces better coverage than any single source, provided everything lands in one consistent format rather than four incompatible exports.

See also Prospecting, Data Enrichment, Email Verification, ICP, Lead List Hygiene

Also called Marketing Qualified Lead, Sales Qualified Lead

An MQL is a lead marketing judges worth passing to sales; an SQL is one sales has accepted as a genuine opportunity worth working.

The two stages exist to make the handoff explicit and measurable. The ratio between them is one of the more honest numbers in a go-to-market operation: a low MQL-to-SQL conversion means marketing is passing leads that do not qualify, or that the definitions were never agreed. Both definitions should be written down and revisited, because the most common failure is each team quietly using its own and reporting incompatible numbers to the same meeting.

See also Lead, Lead Scoring, SDR and BDR, Conversion Rate

Multi-threading is deliberately building relationships with several people inside the same target account rather than relying on a single contact.

B2B purchases of any size involve a group: a user who feels the problem, a manager who owns the budget, and often security, finance or legal. Single-threaded deals fail for reasons that have nothing to do with the product: the contact leaves, gets reassigned, or simply cannot get it approved. Multi-threading means the deal survives that. It requires care in outbound, since several people at one company receiving near-identical messages reads as spam rather than coordination.

See also Account-Based Marketing, Outreach, ICP

Also called Mail Exchange Record

An MX record is the DNS entry that tells the internet which servers receive email for a domain.

Without an MX record a domain cannot accept mail at all, so its absence is a definitive invalid result during verification and costs nothing to check. MX records are also useful intelligence beyond validation: they reveal which mail provider a company uses, which is a technographic signal you can segment on. A domain whose MX points at Google Workspace behaves differently from one on Microsoft 365, and both differ from one running its own server.

See also Email Verification, Hard Bounce, Technographics

Also called Daily Registered Domains

A newly registered domain is one bought within the last days or weeks, and the daily register of them is a public feed of businesses that have just started.

A company registers its domain before it hires, chooses tools or signs vendors, which makes the register an early buying signal for anyone selling to new businesses: web services, branding, hosting, accounting, recruitment. The window is what makes it valuable: reach the owner in the first fortnight and you are the first approach rather than the twentieth. The trade-off is volume and noise, since a large share of new registrations are parked, speculative or never developed, so filtering matters as much as speed.

• Daily registered domains

See also Buyer Intent, Prospecting, Domain Reputation

Open rate is the percentage of delivered emails that were opened, measured by a tracking pixel loading in the recipient's client.

Open rate has become substantially less reliable than it used to be. Apple's Mail Privacy Protection pre-loads tracking pixels regardless of whether anyone read the message, and other clients block them entirely, so the figure over-reports on some segments and under-reports on others. It retains value as a relative signal, since a sharp drop across a campaign usually means a deliverability problem rather than a copy problem, but it is no longer a sound basis for judging subject lines, and reply rate is the better primary metric.

See also Reply Rate, Inbox Placement, A/B Testing, Click-Through Rate

Opt-in is explicit permission given by a person to receive communications from you.

Opt-in is the standard required by GDPR-adjacent regimes and is the basis on which newsletters and lifecycle email operate. It must be a clear affirmative action (a pre-ticked box is not consent) and you should record when and how it was given, because the burden of proving it falls on you. Cold outreach by definition has no opt-in, which is precisely why it depends on a different lawful basis and on tighter self-imposed limits.

See also Double Opt-In, GDPR, CAN-SPAM, Unsubscribe

Outreach is the act of contacting prospects directly, by email, phone, social message or post, to start a conversation.

Outreach is the visible end of a process that is mostly invisible: the quality of the list, the verification, and the segmentation determine most of the result before the first message is sent. Multi-channel outreach, combining email with a call or a social touch, generally outperforms any single channel, largely because it produces more attempts without increasing the volume through any one of them. The constraint is always relevance, never reach.

See also Cold Email, Cold Outreach Sequence, Follow-Up, Personalization, Multi-Threading

Personalisation is tailoring an outreach message to the specific recipient using what you actually know about them and their company.

There is a real distinction between merge-field personalisation (inserting a first name and a company) and relevance, which means the message would not make sense sent to anyone else. The first is invisible at best and conspicuous when the data is wrong; the second is what produces replies. Segmenting a list and writing a genuinely specific message per segment usually outperforms individually personalising a generic one, and it scales, which individual research does not.

See also Data Enrichment, Cold Email, Reply Rate, Role-Based Email

Prospecting is the research step that turns a market into a specific list of accounts and named people worth contacting.

Prospecting is where outbound is won or lost, and it happens before a word of copy is written. It means defining the profile, sourcing accounts that match, finding the right person inside each one, and verifying you can reach them. Teams that treat it as an afterthought end up compensating with volume, which is what produces complaint rates and burnt domains. A small, well-researched list consistently outperforms a large indiscriminate one on every metric that matters.

See also List Building, ICP, Lead Generation, SDR and BDR, Newly Registered Domain

Reply rate is the percentage of delivered emails that received a response, positive or negative.

Reply rate is the most trustworthy metric in cold outreach because, unlike opens, it cannot be inflated by privacy proxies and, unlike clicks, it requires real intent. It is worth splitting into positive and negative replies, since a high overall rate driven by people asking to be removed is a warning rather than a success. What moves it is relevance (segmentation and a specific ask) far more than subject-line experimentation.

See also Open Rate, Personalization, Cold Outreach Sequence, Conversion Rate

A role-based address belongs to a function rather than a person (info@, sales@, support@, admin@) and is typically read by several people or none.

Role addresses are valid and will not bounce, which makes them look like good data, but they convert poorly and complain disproportionately: nobody feels personally addressed, and shared inboxes are quick to mark unsolicited mail as spam. Some blocklist operators also treat heavy role-address sending as a scraping signal. Most verifiers flag them so you can exclude them. They have a place in support and billing workflows; they do not belong in a cold sequence written in the second person.

See also Email Verification, Spam Complaint, Personalization

Also called Sales Development Representative, Business Development Representative

An SDR or BDR is a salesperson whose job is to generate and qualify new opportunities and hand them to an account executive, rather than to close deals.

The split exists because prospecting and closing reward different skills and different rhythms, and because an account executive doing their own prospecting will always do it last. Conventionally BDRs work outbound, on cold lists, while SDRs qualify inbound, though the titles are used interchangeably in practice. The role lives or dies on list quality: the most common cause of SDR underperformance is not effort or script, it is being handed a list nobody qualified.

See also Prospecting, Lead, MQL and SQL, Outreach

Sender reputation is the score inbox providers assign to your sending domain and IP address based on how recipients have responded to your mail over time.

Every major provider keeps a running score on you. It is driven by complaint rate, bounce rate, how often recipients open, reply, delete without reading, or mark as spam, and whether you have hit spam traps. Reputation is slow to build and fast to lose. A single bad send to a stale list can undo months. It attaches to both the domain and the IP, which is why sending from a subdomain is common practice: it isolates cold outreach from the domain your invoices and support email go out on.

See also Domain Reputation, Deliverability, Spam Complaint, Bounce Rate, Email Warm-up

A soft bounce is a temporary delivery failure (a full mailbox, a server that is down, or a message rejected for size) that may succeed on a later attempt.

Soft bounces are retried automatically by most sending platforms over a period of hours or days. They are less damaging than hard bounces, but a persistent soft bounce is usually a hard bounce in disguise: a mailbox that has been full for a month belongs to someone who has left. A sensible rule is to retry a few times and then suppress. Repeated deferrals from one provider can also indicate throttling rather than a problem with the address itself.

See also Hard Bounce, Bounce Rate, Email Throttling

Also called Complaint Rate

A spam complaint is recorded when a recipient marks your message as junk, and the complaint rate is the share of delivered messages that receive one.

Complaints are the most damaging single signal in email, because they are an explicit human judgement rather than an inference. Google and Yahoo both require bulk senders to stay under 0.3%, and treat 0.1% as the level you should actually be operating at. That is one complaint in a thousand. Complaint rate is driven less by list quality than by relevance and by how obvious the unsubscribe is: burying it reliably converts an opt-out into a complaint, which costs you far more.

See also Sender Reputation, Unsubscribe Rate, Deliverability, CAN-SPAM

Also called Honeypot

A spam trap is an email address created or repurposed by a provider or blocklist operator purely to catch senders who are mailing lists they did not earn.

There are two kinds. Pristine traps are addresses never used by a human and published where only a scraper would find them, so hitting one proves you harvested rather than collected. Recycled traps are real addresses abandoned long ago and reactivated as traps, so hitting one proves your list is stale and you are not removing non-responders. Traps are invisible (they never bounce and never complain), so the only defence is verification and disciplined list hygiene.

See also Lead List Hygiene, Email Verification, Blocklist, Data Decay

Also called Sender Policy Framework

SPF is a DNS record listing which mail servers are permitted to send email on behalf of your domain.

SPF publishes a TXT record at your domain naming the servers allowed to send as you. A receiving server checks the sending IP against that list and treats a mismatch as a signal of forgery. Two things commonly break it: the ten-lookup limit, which quietly invalidates the record when you chain too many third-party includes, and forwarding, which changes the sending server and fails the check through no fault of yours. SPF alone proves very little. It is one of three records, and DMARC is what ties them together.

See also DKIM, DMARC, Deliverability, Domain Reputation

Also called Total Addressable Market

Total addressable market is the full set of companies that could plausibly buy your product, and in outbound terms the total number of accounts your profile matches.

For outbound, TAM is a countable and very practical number: run your ideal customer profile as a filter and see how many accounts come back. That count determines strategy more than anything else. A TAM of a few hundred accounts means account-based work and multi-threading, because you cannot afford to burn any of them. A TAM in the hundreds of thousands supports volume, segmentation and testing. Teams frequently run tactics suited to the wrong one.

See also ICP, Firmographics, Account-Based Marketing, Prospecting

Technographics are data about the software and infrastructure a company uses: its CRM, analytics, hosting, payment processor and marketing stack.

Technographics are among the strongest intent-adjacent signals available, because a company's stack tells you what it has already committed to and what it is likely to need next. They support both targeting (anyone running a competing product is a displacement opportunity) and personalisation, since referencing a tool the recipient actually uses is specific in a way that generic personalisation is not. Sources include page markup, DNS and MX records, job postings and public integration directories.

See also Firmographics, Buyer Intent, MX Record, ICP

Also called Opt-Out

An unsubscribe is a recipient's request to stop receiving your emails, which you are legally required to provide a mechanism for and to honour.

Every commercial message needs a clear, working way out. Since 2024, bulk senders to Google and Yahoo must support one-click unsubscribe via the List-Unsubscribe header and process requests within two days; CAN-SPAM allows ten business days and forbids charging or requiring a login. Beyond the legal minimum, making it easy is straightforwardly in your interest: the alternative the recipient reaches for is the spam button, which damages your reputation permanently rather than removing one address.

See also Unsubscribe Rate, Spam Complaint, CAN-SPAM, GDPR

Unsubscribe rate is the percentage of delivered emails that resulted in the recipient opting out of further contact.

Unsubscribes look like a loss and are usually the opposite: every opt-out is someone who chose not to press the spam button instead, which would have cost you far more. A visible, working, one-click unsubscribe is now required by Google and Yahoo for bulk senders, and burying it reliably converts opt-outs into complaints. A rising unsubscribe rate is a relevance signal: the list is wrong, or the message is. It is best read next to complaint rate rather than alone.

See also Spam Complaint, Lead List Hygiene, CAN-SPAM, Unsubscribe

Waterfall enrichment queries several data sources in sequence, falling through to the next only when the previous one returns nothing for that record.

No single provider has complete coverage, and coverage varies by geography, company size and seniority. A waterfall runs the cheapest or highest-confidence source first and only pays for the next when the field is still missing, which lifts overall fill rate while keeping cost per enriched record down. The trade-off is consistency: fields sourced from different providers can disagree, so it is worth recording which source supplied each value rather than silently overwriting.

See also Data Enrichment, Contact Enrichment, Company Enrichment