Web analytics is the collection and study of data about how people find and use a website: where they came from, which pages they read, what they clicked and whether they went on to buy, book or enquire. Its job is to show what is working so you can decide what to change.
How web analytics works
Most tools work by placing a small script on every page. When someone visits, the script records events (a page view, a scroll, a click, a form submission) and sends them to the analytics service with details such as the page, the referring source and the device. A cookie or similar identifier usually lets the tool recognise the same browser on a later visit.
The service then turns those raw events into reports built from two kinds of data. Metrics are numbers, such as sessions, users or conversions. Dimensions are descriptions, such as traffic source, page or city. Every useful report is a metric split by a dimension, for example enquiries by traffic source.
The main tools in use in the UK include:
- Google Analytics 4 Free and the most common, closely linked to Google Ads.
- Privacy-focused tools such as Matomo, Plausible and Fathom, which collect less data and in some setups avoid cookies altogether.
- Behaviour tools such as Microsoft Clarity and Hotjar, which add heatmaps and session recordings on top of the numbers.
Some data never reaches the tool at all. Ad blockers, browsers that limit tracking, and visitors who decline cookies all leave gaps, so analytics shows a sample of your audience rather than all of it.
Why it matters
Without analytics, marketing decisions rest on opinion. With it, a business can see that most enquiries arrive through a handful of service pages, that mobile visitors abandon a long form halfway, or that a paid campaign brings plenty of visits and almost no leads. Those findings point to specific fixes.
In the UK, consent sits at the centre of how analytics is set up. Under PECR, storing or reading information on a visitor’s device needs their consent unless it is strictly necessary for the service they asked for, and the ICO has long treated analytics cookies as not strictly necessary. The Data (Use and Access) Act 2025 introduces a narrow exception for some analytics used only to measure and improve your own website, provided visitors are told clearly and can object easily. It does not cover tags that share data with advertising platforms for their own purposes. Whether it applies to your setup depends on the provision being in force and on the ICO’s guidance at the time (this entry was written in October 2026), so check the current position before relying on it.
The practical effect is that a compliant UK site usually records fewer visitors than a non-compliant one, and figures drop when a proper cookie banner goes live. That drop reflects measurement, not demand.
Common mistakes
- Installing analytics but never defining what counts as a conversion, so reports show traffic and nothing about results.
- Loading analytics before consent is given, which breaks PECR for UK visitors.
- Reading totals rather than trends, and reacting to a quiet week as if it were a crisis.
- Counting your own staff visits, which can distort small sites badly.
- Leaving campaign links untagged, so email and social traffic lands in “direct”.
- Treating analytics figures as exact counts rather than a sample shaped by consent and blockers.
How to act on it
Start with a short measurement plan: the two or three actions that matter most to your business, such as a booked call, a quote request or a purchase, and how each will be recorded. Set those up as conversions and test them.
Make sure your consent banner controls when analytics loads, and note the date it went live in your reports. Tag campaign links with UTM parameters, exclude internal traffic, and build one simple monthly view that shows conversions by channel and by key page.
Then use the data to make one decision at a time: fix the page with the highest exit rate on the enquiry route, or move budget away from a channel that brings visits without leads. Setting up measurement that answers commercial questions is part of the performance marketing work I do with UK businesses.