The terms of tracking and analytics, defined plainly.
What each term means, how it works, and how to check it on your own site.
- Attribution model: definition and the models left in 2026
- An attribution model is the rule or algorithm that decides how credit for a conversion is shared between the marketing touchpoints that preceded it, such as ad clicks and site visits. In GA4 and Google Ads the main choices in 2026 are data-driven attribution and last click, since Google removed first click, linear, time decay and position-based models in 2023.
- Consent Mode (Google): definition and how it works
- Consent Mode is Google's API for passing a visitor's consent choices to Google tags, so that Google Analytics, Google Ads and Floodlight tags change how they store and send data depending on whether consent was granted or denied. It uses four main consent types (ad_storage, analytics_storage, ad_user_data and ad_personalization) and can be implemented in a basic or an advanced way.
- Conversions API (Meta): definition, deduplication and checks
- The Conversions API (CAPI) is Meta's interface for sending marketing events, such as purchases and leads, from your server directly to Meta instead of only from the browser through the Meta pixel. It is usually run alongside the pixel, with a shared event ID so Meta can remove duplicates.
- dataLayer: what it is and how Google Tag Manager uses it
- The dataLayer is a JavaScript array on a web page, named window.dataLayer by default, that the website uses to pass events and values to Google Tag Manager and gtag.js. Developers push structured objects into it, and tags, triggers and variables read from it, so tracking does not depend on scraping the page.
- Enhanced conversions (Google Ads): definition and setup checks
- Enhanced conversions is a Google Ads feature that supplements conversion tags with first-party customer data, such as an email address or phone number, hashed with SHA-256 and matched to signed-in Google accounts. It recovers conversions that cookies and click IDs alone would miss and gives bidding more accurate data.
- GA4 Measurement Protocol: definition, limits and checks
- The GA4 Measurement Protocol is an HTTP interface for sending events directly to a Google Analytics 4 property from servers, back-office systems or devices, without a browser tag. Google designed it to supplement the Google tag, Tag Manager and Firebase, not to replace them.
- Generative engine optimisation (GEO): definition and measurement
- Generative engine optimisation (GEO) is the practice of making content more likely to be used and cited as a source in answers produced by generative AI systems, such as ChatGPT, Gemini, Claude, Perplexity and Google's AI Overviews and AI Mode. The term comes from a 2023 research paper by Aggarwal and colleagues, presented at KDD 2024.
- Incrementality: definition, lift tests and how to read them
- Incrementality is the share of conversions, revenue or other outcomes that happened because of a marketing activity and would not have happened without it. It is measured by comparing a group exposed to the activity with a comparable control group that was not, for example in a conversion lift or geo experiment.
- Marketing mix modelling (MMM): definition and checks
- Marketing mix modelling (MMM) is a statistical method that estimates how much each marketing channel and other factors, such as price, seasonality and promotions, contributed to sales or another KPI, using aggregated time-series data rather than user-level tracking. It is used to measure return on investment by channel and to plan budget allocation.
- Server-side tagging: definition, costs and checks
- Server-side tagging is a setup in which the browser or app sends measurement data to a tagging server you control, usually a Google Tag Manager server container, and that server forwards the data to analytics and advertising platforms. It moves tag processing off the website, so you decide what each vendor receives.