Question 1

What is the difference between a cookie, a tracking pixel and server-side tagging?

Accepted Answer

They are three different mechanisms for the same job — recognising visitors and recording what they did — operating at different layers.

**A cookie** is a small file a website stores in your browser. **First-party cookies** are set by the site you are on, and do useful work: keeping you logged in, remembering a basket, storing preferences. **Third-party cookies** are set by a different domain embedded in the page, typically an advertising network, and are what allowed tracking across unrelated sites. Browsers have progressively restricted them — Safari and Firefox block them by default, and Chrome's plans have shifted repeatedly — which is the single biggest disruption to digital advertising in years.

**A tracking pixel** is a tiny piece of code, historically a 1×1 transparent image, that fires a request to a third party when a page loads or an action occurs. Loading the pixel tells the advertiser you were there. Pixels are how conversion tracking, retargeting audiences and analytics events are usually implemented, and they typically set or read cookies as part of the process. **Email open tracking** works the same way, which is why blocking remote images blocks it.

**Server-side tagging** moves the collection off the browser. Instead of the visitor's browser sending data directly to a dozen third parties, it sends one request to a server you control, which then forwards data onward.

**Why server-side has grown:** it survives browser tracking restrictions and ad blockers better, improves page speed by removing third-party scripts, and gives you control over what leaves your infrastructure.

**The honest caveat:** it also makes tracking less visible to the user and harder to block, which is precisely why privacy advocates object. Consent obligations under GDPR and similar laws apply to what you do with the data, not to where the code runs — moving collection server-side does not remove the need for lawful basis and consent.

Question 2

What is consent mode, and what happens without consent?

Accepted Answer

A mechanism by which analytics and advertising tags adjust their behaviour according to whether a user has consented — sending limited, non-identifying signals rather than either full tracking or

Question 3

How do ad blockers affect marketing measurement?

Accepted Answer

They remove a non-random slice of your audience from the data, which distorts more than the raw blocking rate suggests — and the browsers themselves now do much of the blocking, independently of

Question 4

What is the difference between first-party, second-party, third-party and zero-party data?

Accepted Answer

Who collected it and from whom — a distinction that became central as third-party tracking was restricted. First-party data. Collected by you, directly from your own customers and visitors, through

Question 5

What is marketing mix modelling and why is it coming back?

Accepted Answer

Marketing mix modelling (MMM) is a statistical technique estimating how different marketing activities contribute to sales, using aggregate historical data rather than tracking individuals. How it

Question 6

What is a retail media network, and why is every retailer building one?

Accepted Answer

A retailer selling advertising inventory against its own shopper data — on its website, in its app, in physical stores, and increasingly on other websites entirely. It has become the fastest-growing

Question 7

How does affiliate marketing actually work, and who gets paid for what?

Accepted Answer

A performance model where a third party — a publisher, creator or comparison site — sends traffic to a merchant and is paid only when a defined action occurs, usually a sale. The mechanics are

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