Cookie stuffing, also known as cookie dropping, is when multiple cookies are dropped after someone views a page or clicks on a single link. It is an illegal affiliate marketing practice where a third-party cookie from a website unrelated to that which is visited by the user is dropped in the background without the visitor’s knowledge.
Cookie stuffing can be a relatively difficult illegal marketing practice to track and catch. Cookie stuffing generally occurs in relatively subtle ways, through pop-ups, scripts, toolbars, or images embedded in message boards. As Forensiq CEO David Sendroff explains for Digiday, “With cookie stuffing, you’re committing a crime against another affiliate or the advertisers who is paying commissions on sales that would have happened anyway. It’s not as eye-opening and it’s harder to catch because the advertiser has still made money.”