What Is Tracking?

In digital marketing, tracking is the umbrella term for every technique that records interactions: which page was visited, where the visitor came from, which button was clicked, whether a purchase was completed. Those data feed metrics such as traffic, conversion rate or the performance of each channel.

The techniques vary. JavaScript tags, like Google Analytics, run in the browser and usually store cookies or identifiers. Tracking pixels are tiny images or invisible requests that tell a server when a page loads or an email is opened. Tracking links add parameters to the URL, such as UTM parameters or affiliate codes. And server-side tracking sends the data from the website's server instead of the browser.

In SEO, the word also has a use that has nothing to do with people: tracking rankings in Google or a brand's visibility in AI answers. There, what gets recorded is search results and model answers, not visitor behaviour.

On a typical website, a tag manager such as Google Tag Manager loads the various measurement scripts and decides when they fire. Each relevant interaction is sent as an event to the analytics tool, which ties it to a session and, if there are cookies, to a returning user.

In Europe, that process depends on consent. The European Data Protection Board's Guidelines 2/2023, in version 2.0 adopted on 7 October 2024, clarify the technical scope of Article 5(3) of the ePrivacy Directive and deal explicitly with tracking pixels and tracking links: a pixel can point to an entity that collects many such requests and so tracks users' behaviour. For anything that is not strictly necessary, the general rule is to ask permission first.

Google offers consent mode for this, in two variants. In the basic one, Google tags do not load until the person responds to the cookie notice, and no data is sent beforehand. In the advanced one, tags load with permissions denied and send cookieless pings, which Google uses to model conversions.

For SEO, tracking is what connects rankings to the business. Search Console shows how many clicks come from Google, but not what those people did next. Without reliable tracking you cannot tell which pages bring enquiries, sales or sign-ups, or compare organic traffic with other channels.

It also defines what stays invisible. Everyone who declines analytics cookies disappears from the reports, or appears only as modelled data. That is why the figures in an analytics tool and in Search Console never fully match, and both are best read knowing what each one leaves out.

On zds.es we apply the strictest form, as the consent library's public configuration file shows: apart from essential cookies, the only service configured is Google Tag Manager, and its code is only inserted once the visitor accepts analytics cookies. That is the basic variant of consent mode: before consent, no measurement script loads at all. And anyone browsing without JavaScript cannot give consent, so they are not measured either (checked on 8 October 2026).

• Before measuring, decide which business questions the data must answer and which events that requires.
• Ask for consent before loading any tracking that is not strictly necessary.
• Use a tag manager to control in one place what loads and when.
• Tag links from your own campaigns with UTM parameters so their traffic is not mistaken for organic.
• Record how much traffic is missing for lack of consent before drawing conclusions from reports.
• Regularly check which scripts the site actually loads, because plugins and tools add tags without warning.

• Loading analytics or advertising tags before the visitor has responded to the cookie notice.
• Measuring everything possible without a concrete question and ending up with reports nobody uses.
• Putting UTM parameters on internal links within your own site, which breaks session attribution.
• Comparing Google Analytics and Search Console figures as if they measured the same thing.
• Forgetting old tags from tools no longer in use that keep sending data.