What Is Affiliate Marketing? A Plain-English Guide

If you have ever clicked a "best laptops" article, followed a link to buy one, and assumed the writer earned something from the sale — you have already met affiliate marketing. It quietly powers a huge slice of the recommendations you see online, from review sites to creators' "shop my links" pages. For businesses, it is one of the few marketing models where you largely pay for results rather than for attention. This guide explains how affiliate marketing works, how the money flows, and the UK rules you must follow.

What it is

Affiliate marketing is a model in which a business rewards external partners — affiliates — with a commission for each customer, lead or sale they refer. Instead of paying upfront for advertising and hoping it works, the business pays a partner a cut after their promotion produces a defined result.

The arrangement involves three parties: the merchant (the business with something to sell), the affiliate (the partner who promotes it), and the customer (the person who acts on the recommendation). Often a fourth element sits in the middle — an affiliate network or platform that connects merchants with affiliates and handles the tracking and payments.

The defining feature of affiliate marketing is that it is performance-based. In most programmes the merchant only pays when the agreed action happens, which is what makes it attractive to businesses wary of spending on advertising that may not deliver.

How the money actually flows

The mechanism is simpler than it sounds. Each affiliate is given a unique tracking link to the merchant's product or site. When someone clicks that link, a small piece of tracking — typically a cookie — records which affiliate sent them. If that person then completes the action the merchant is paying for, the system credits the right affiliate, and a commission is due.

What counts as the "action" varies by programme:

• Pay per sale — the most common: commission only when a purchase is made.
• Pay per lead — commission when someone takes a step like signing up or requesting a quote.
• Pay per click — commission for sending traffic, regardless of whether it converts (less common, and more open to abuse).

Tracking is imperfect — cookies can be blocked, expire, or miss cross-device journeys — so attribution is an approximation rather than a perfect ledger. That is true across digital marketing, and our guide to measuring marketing ROI explains why it pays to treat such numbers as a sensible guide rather than gospel.

Why businesses use it

Affiliate marketing has a particular appeal for businesses that are cautious with budget:

1. You mostly pay for results. Because commission is tied to a real action, much of the risk of "spending and hoping" shifts to the affiliate.
2. It scales with partners. Each new affiliate is another channel reaching an audience you might not otherwise touch.
3. It borrows trust. A recommendation from a creator or site the audience already follows carries more weight than a banner ad — the same reason a genuine customer testimonial is so persuasive.

It is not free of cost or effort, though. You still need a competitive commission, good promotional materials, reliable tracking, and time to recruit and manage partners. And it only makes sense where the economics work: a product with thin margins cannot sustain a meaningful commission. Thinking through your numbers, in the spirit of pricing your product sensibly, tells you whether affiliate commission is even affordable.

The UK rules you cannot ignore

This is the part too many people get wrong. In the UK, the principle is firm: anyone promoting a product for a commission must make that commercial relationship clear. Audiences are entitled to know when a recommendation could earn the recommender money, because that knowledge affects how much weight they give it.

The Advertising Standards Authority (ASA) enforces the advertising codes, and the Competition and Markets Authority (CMA) backs them with consumer protection law. In practice this means:

• Affiliate links and content must be obviously identifiable as marketing. A clear label — making it plain the content contains affiliate links — is the safe approach.
• Disclosure must be prominent, not buried in the small print or hidden behind a "more" tap.
• The obligation applies on social media too, and to "shop my links" pages, round-ups and reviews alike.

Hidden affiliate links risk breaching the codes and consumer law, and they erode the very trust that makes a recommendation valuable. This article is general guidance, not legal advice; the ASA's own guidance is the authoritative source.

Affiliate vs influencer marketing

People often blur the two, but the difference is in how the partner is paid. Influencer marketing typically pays a creator a flat fee to promote a brand, whether or not it leads to sales. Affiliate marketing pays purely on performance — a commission only when a referral converts. The two can be combined: a creator might take a fee and earn affiliate commission on the sales they drive. Either way, the disclosure rules apply.

Running an affiliate programme well

If you decide affiliate marketing fits your business, a few habits separate effective programmes from wasted effort:

• Choose partners for relevance, not reach. An affiliate whose audience genuinely matches your customer will outperform a bigger but mismatched one.
• Set fair, sustainable commission. Too low and no good affiliate will bother; too high and the maths stops working. Anchor it to your margins.
• Give affiliates what they need. Clear product information, accurate links and honest selling points make it easy for partners to promote you well.
• Insist on honest disclosure. Protecting compliance protects your brand; make disclosure expectations explicit in your agreements.

The bottom line

Affiliate marketing rewards partners with a commission for the customers, leads or sales they bring you, making it a largely performance-based way to grow. It runs on unique tracking links that connect a result back to the affiliate who earned it, and it works best for products with healthy margins and the right, relevant partners. In the UK, the non-negotiable is disclosure: any affiliate relationship must be made clear, because audiences deserve to know when a recommendation could earn someone money. Treated as a transparent, well-managed channel rather than a hidden one, affiliate marketing can extend your reach while keeping your risk — and your spending — tied to real results.