Glossary
Analytics & growth glossary
Short, precise definitions of the 84 terms founders and marketers meet in web analytics, attribution, SaaS metrics, privacy law and SEO. Each entry opens with a one-sentence definition, then shows how the number is calculated, a worked example, and the mistakes that make it lie.
Updated
All terms, A–Z
A
- Activation rateActivation rate is the percentage of new sign-ups who reach a defined "activation" milestone — the first moment they get real value from the product, such as creating a first project or seeing their first data.
- Ad blockers (and analytics)Ad blockers are browser extensions and built-in browser features that stop ads and tracking requests from loading; most also block popular analytics scripts, so visitors using them disappear from client-side analytics entirely.
- AI crawlersAI crawlers are automated bots operated by AI companies that fetch web pages — either to collect training data for models, to index content for AI search, or live, to answer a user's question in an assistant like ChatGPT, Claude or Perplexity.
- AI OverviewsAI Overviews are AI-generated summaries that Google Search shows above the regular results for some queries, combining information from several web pages and linking to sources.
- Annual recurring revenue (ARR)Annual recurring revenue (ARR) is the yearly value of a company's active recurring subscription contracts — for most SaaS companies, MRR multiplied by 12.
- Answer engine optimization (AEO)Answer engine optimization (AEO) is the practice of structuring content so that search engines and assistants can use it as the direct answer to a question — in featured snippets, People Also Ask boxes, voice assistants and AI-generated answers.
- Attribution windowAn attribution window, or lookback window, is the maximum time between an ad interaction or visit and a conversion for that interaction to receive credit for it.
- Average revenue per user (ARPU)Average revenue per user (ARPU) is the average amount of revenue a business earns per user or account over a period, usually per month — calculated as revenue divided by the number of users.
- Average session durationAverage session duration is the mean length of time between the first and last recorded activity in a session, averaged across all sessions in a period.
B
- Bot trafficBot traffic is any website visit made by automated software rather than a person — search crawlers, AI crawlers, uptime monitors, scrapers, headless browsers and spam bots.
- Bounce rateBounce rate is the percentage of sessions in which a visitor viewed only one page and left without viewing a second page.
- Browser fingerprintingBrowser fingerprinting is a technique that identifies or tracks a device by combining many of its observable characteristics — user agent, screen size, installed fonts, time zone, graphics hardware, audio and canvas rendering — into an identifier that persists without cookies.
C
- CAC payback periodCAC payback period is the number of months it takes for a new customer's gross profit to cover the cost of acquiring them.
- Canonical URLA canonical URL is the preferred version of a web page that search engines should index and rank when the same or very similar content is available at several URLs, usually declared with a rel="canonical" link element.
- CCPAThe CCPA, the California Consumer Privacy Act — as amended by the California Privacy Rights Act (CPRA) — is California's consumer privacy law, giving California residents rights over their personal information and requiring covered businesses to honor opt-outs from selling or sharing it.
- Channel groupingChannel grouping is the set of rules an analytics tool uses to sort every visit into a marketing channel — such as direct, organic search, paid search, social, email or referral — based on its referrer, UTM parameters and ad click ids.
- Churn rateChurn rate is the percentage of customers (or recurring revenue) that a business loses during a period, out of the customers (or revenue) it had at the start of that period.
- Click IDA click ID is a unique identifier that an ad platform or social network appends to a link's URL when someone clicks it — such as gclid for Google Ads, fbclid for Meta or twclid for X — so the click can be matched to a later conversion.
- Click-through rate (CTR)Click-through rate (CTR) is the percentage of people who clicked a link out of everyone who saw it — clicks divided by impressions.
- Cohort analysisCohort analysis is a method of grouping users by a shared starting event — usually the week or month they first visited or signed up — and comparing how each group behaves over the same time since that start.
- Consent bannerA consent banner, or cookie banner, is the notice a website shows to ask visitors for permission before storing or reading non-essential cookies and similar identifiers on their device, and to record their choice.
- Conversion funnelA conversion funnel is an ordered sequence of steps a visitor takes toward a goal — for example landing page, pricing, sign-up, payment — measured as how many visitors reach each step and how many drop off between them.
- Conversion rateConversion rate is the percentage of visitors (or sessions) that complete a desired action — a sign-up, purchase, demo request or any other goal — out of all visitors (or sessions) in the same period.
- Cookieless trackingCookieless tracking is web analytics that counts visitors without storing any identifier on the visitor's device — no cookies, localStorage or similar — typically by deriving a short-lived anonymous id on the server instead.
- Crawl budgetCrawl budget is the number of URLs on a site that a search engine crawler can and wants to crawl in a given period — determined, in Google's terms, by crawl capacity (how much your server can handle) and crawl demand (how much Google wants to recrawl your content).
- Custom eventsCustom events are events you define and send to your analytics tool yourself — such as signup, demo_booked or plan_upgraded — to record actions that are specific to your product and can't be detected automatically.
- Customer acquisition cost (CAC)Customer acquisition cost (CAC) is the total sales and marketing spend required to acquire one new paying customer over a period — total acquisition costs divided by new customers acquired.
- Customer lifetime value (LTV)Customer lifetime value (LTV or CLV) is the total revenue — or, more usefully, gross profit — a business can expect from a single customer over the whole time they remain a customer.
D
- Dark socialDark social is traffic from links shared through private channels — messaging apps, email, Slack, text messages, closed communities — that arrives without a referrer, so analytics tools record it as direct traffic.
- Data samplingData sampling in analytics is calculating a report from a subset of the collected data and scaling the result up to estimate the total, instead of processing every event.
- Direct trafficDirect traffic is any visit that arrives with no referrer and no campaign parameters, so the analytics tool can't tell where it came from and files it as "direct" or "(none)".
E
- Engagement rateEngagement rate is the percentage of sessions that counted as engaged — in Google Analytics 4, sessions that lasted at least 10 seconds, viewed two or more pages, or triggered a key event.
- Entry pageAn entry page is the first page a visitor views in a session — the page through which they entered the site on that visit.
- ePrivacy DirectiveThe ePrivacy Directive (Directive 2002/58/EC, amended in 2009) is the EU law on privacy in electronic communications whose Article 5(3) requires consent before storing information on, or reading it from, a user's device — which is why it's called the "cookie law."
- Event trackingEvent tracking is recording specific actions visitors take on a website or app — clicks, form submissions, sign-ups, downloads, purchases — as named events, often with properties that describe them.
- Exit pageAn exit page is the last page a visitor viewed in a session before leaving the site; exit rate is the share of a page's views that were the last in their session.
- Expansion revenueExpansion revenue is additional recurring revenue earned from existing customers — through plan upgrades, extra seats, add-ons or higher usage — as opposed to revenue from new customers.
F
- First-party proxyA first-party proxy is a setup where the analytics script and the endpoint it reports to are served from your own domain — through a rewrite, reverse proxy or CDN rule — so the browser treats the requests as first-party instead of calls to a third-party analytics domain.
- First-party vs third-party cookiesA first-party cookie is set by the website you are visiting, under its own domain; a third-party cookie is set by a different domain embedded in that page — such as an ad network or social widget — and can follow you across every site that embeds it.
- First-touch attributionFirst-touch attribution is an attribution model that gives 100% of the credit for a conversion or payment to the source of the visitor's very first visit, ignoring every visit that came after it.
- Funnel drop-offFunnel drop-off is the share of visitors who complete one step of a funnel but don't reach the next one — the leak between two stages of a conversion path.
G
- GDPRGDPR, the General Data Protection Regulation (Regulation (EU) 2016/679), is the European Union law that governs how personal data about people in the EU is collected, used and stored, in force since May 25, 2018.
- Generative engine optimization (GEO)Generative engine optimization (GEO) is the practice of shaping a website's content and technical setup so that AI-powered answer engines — ChatGPT search, Perplexity, Google AI Overviews, Claude, Copilot — retrieve it, cite it and mention it in their generated answers.
- GoalA goal, or conversion goal, is a visitor action that you define in your analytics tool as a success — reaching a page, firing an event, completing a purchase — so the tool can count it and calculate a conversion rate for it.
- Google Search ConsoleGoogle Search Console is Google's free service that shows how a website performs in Google Search — the queries it appears for, its clicks, impressions, click-through rate and average position — and reports on crawling, indexing and technical issues.
I
- ImpressionsImpressions are the number of times a piece of content — a search result, an ad, a post — was displayed to users, whether or not anyone clicked it.
- IP anonymizationIP anonymization is the practice of removing, truncating or otherwise obscuring a visitor's IP address in an analytics or logging system so the stored data can't be traced back to a specific connection.
L
- Landing pageA landing page is the page a visitor first arrives on from a link, ad or search result — and, in marketing, a standalone page designed for one campaign with a single call to action.
- Last-touch attributionLast-touch attribution is an attribution model that gives 100% of the credit for a conversion to the source of the last visit before it happened.
- Linear attributionLinear attribution is a multi-touch attribution model that splits the credit for a conversion equally across every touchpoint in the customer's path.
- llms.txtllms.txt is a proposed standard for a Markdown file served at a website's root (/llms.txt) that gives large language models and AI tools a concise, curated summary of the site and links to its most useful content.
- LTV:CAC ratioThe LTV:CAC ratio compares the lifetime value of a customer with the cost of acquiring them — LTV divided by CAC — to show how much value each dollar of acquisition spend creates.
M
- Micro-conversionA micro-conversion is a smaller action that signals a visitor is moving toward the main goal — such as viewing the pricing page, starting a sign-up form, watching a demo video or copying an install snippet — as opposed to the macro-conversion itself (the sign-up or purchase).
- Monthly recurring revenue (MRR)Monthly recurring revenue (MRR) is the predictable subscription revenue a business expects to earn every month, normalized to a monthly amount and excluding one-time payments.
- Multi-touch attributionMulti-touch attribution is any attribution approach that divides the credit for a conversion across several of the touchpoints that preceded it, instead of giving it all to the first or last one.
N
- Net revenue retention (NRR)Net revenue retention (NRR) is the percentage of recurring revenue a business keeps from an existing group of customers over a period, after adding expansion and subtracting downgrades and churn, excluding new customers.
- North star metricA north star metric is the single measure a company chooses as the best indicator of the value customers get from its product, used to align teams and predict long-term growth.
P
- PageviewA pageview is a single load of a page in a visitor's browser, recorded by an analytics tool each time that page is displayed — including reloads and, on single-page apps, each client-side route change.
- PECRPECR, the Privacy and Electronic Communications Regulations 2003, is the UK law that implements the ePrivacy Directive's rules on cookies and similar technologies, electronic marketing and communications security, enforced by the Information Commissioner's Office (ICO).
- Position-based attributionPosition-based attribution, also called U-shaped attribution, is a multi-touch model that gives 40% of the credit to the first touch, 40% to the last touch and splits the remaining 20% evenly across the touches in between.
R
- Referral trafficReferral traffic is visits that arrive by clicking a link on another website that isn't a search engine, social network or ad — for example a blog post, directory, forum or partner site that links to you.
- ReferrerA referrer is the address of the web page that linked a visitor to the current page, sent by the browser in the HTTP Referer header and exposed to scripts as document.referrer.
- Retention rateRetention rate is the percentage of users or customers from a starting group who are still active — still subscribed, or still coming back — after a given period.
- Revenue attributionRevenue attribution is the practice of connecting each payment to the visitor who made it and the marketing sources — referrer, campaign, landing page — that brought that visitor, so you can see how much money each channel actually produced.
- robots.txtrobots.txt is a plain-text file at the root of a website (/robots.txt) that tells crawlers which URLs they are allowed or not allowed to request, using the Robots Exclusion Protocol, standardized as RFC 9309 in 2022.
S
- Server-side trackingServer-side tracking is sending analytics or conversion events from your own server to the analytics or ad platform, instead of (or in addition to) from a script running in the visitor's browser.
- SessionA session is a group of pageviews and events from one visitor that happen close together in time, and that ends once the visitor has been inactive for a set timeout — usually 30 minutes.
- Session replaySession replay is a feature that records the changes to a web page and a visitor's interactions with it — mouse movement, clicks, scrolling, typing events — and reconstructs them later as a video-like playback of that visit.
- Structured dataStructured data is machine-readable markup added to a web page — usually Schema.org vocabulary written as JSON-LD — that describes what the page contains (an article, product, organization, FAQ, defined term) so search engines and other systems can understand it precisely.
T
- Time-decay attributionTime-decay attribution is a multi-touch attribution model that gives every touchpoint some credit for a conversion, but more to touches that happened closer in time to the conversion.
- Trial conversion rateTrial conversion rate is the percentage of users who start a free trial and go on to become paying customers, measured over trials that have ended.
U
- Unique visitorA unique visitor is a distinct person — in practice a distinct browser or device — that visited a website at least once during a given period, counted only once no matter how many pages they viewed or how often they returned.
- User agentA user agent is the text string a browser, app or bot sends in the User-Agent HTTP header to identify its software, version and platform to the server it's requesting from.
- User identification (identify)User identification is linking an anonymous visitor in your analytics to a known user in your product — usually with an identify call that sends your own user id and, optionally, traits such as plan or sign-up date.
- UTM parametersUTM parameters are five standard query-string tags — utm_source, utm_medium, utm_campaign, utm_term and utm_content — added to a link so analytics tools can attribute the visit to a specific source, channel and campaign.
- utm_campaignutm_campaign is the UTM parameter that names the specific campaign, launch or promotion a link belongs to, so visits and conversions from every channel in that campaign can be grouped together.
- utm_contentutm_content is the UTM parameter used to tell apart different links, creatives or placements within the same campaign — for example two buttons in one email, or two versions of an ad.
- utm_mediumutm_medium is the UTM parameter that describes the type of marketing channel that sent a visit — such as email, cpc, social, referral or affiliate — and is what most tools use to assign the visit to a channel group.
- utm_sourceutm_source is the UTM parameter that identifies the specific site, platform or publisher that sent a visit — for example google, newsletter, x or a partner's name.
- utm_termutm_term is the UTM parameter originally meant for the paid search keyword that triggered an ad, and now commonly used for any targeting detail — a keyword, audience or ad-set name.
Terms by topic
Web analytics · 11
Traffic sources & UTMs · 12
Attribution · 10
Conversion & retention · 10
SaaS metrics · 10
Privacy & compliance · 9
Tracking technology · 12
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