Cookie stuffing

Affiliate programs pay commission to whoever referred a buyer, usually recognised by a cookie set when the shopper clicked the affiliate's link. Cookie stuffing sets that cookie without any genuine referral. A hidden image, invisible frame or script loads the retailer's affiliate link in the background when someone visits an unrelated page. If the person later shops at the retailer on their own, the fraudster collects commission.

It inflates costs for merchants and steals credit from genuine affiliates. The MRC IVT guidelines include cookie stuffing, recycling and harvesting in their list of SIVT, because they manipulate the data used for measurement and targeting. It is closely related to attribution fraud and to click spamming in mobile.

Signs include affiliates with high commissions but very little visible traffic, conversions without matching click paths, many cookies set with zero time on the retailer's site and referrals from pages unrelated to the product. Merchants counter it with click validation, referrer checks and closer auditing of affiliate traffic sources.

Think of it like this

It is like a salesperson slipping their business card into every shopping bag in the mall, then claiming commission whenever anyone who holds one returns to buy.

An example

An online electronics store finds one affiliate credited with $1.2 million in sales a year while sending almost no measurable clicks. Audit shows hidden 1x1 images on its forum pages were setting the affiliate cookie for every visitor.