You don't have to buy stuff directly, or even interact with the ad, you just need to see it; be influenced by it. You'll buy stuff later. When you see an ad for

You don't have to buy stuff directly, or even interact with the ad, you just need to see it; be influenced by it. You'll buy stuff later. When you see an ad for a package holiday you don't have to click it for the ad to be effective (although some people do click them), you may just as well decide to visit the operator's website the next day to browse their options. If their ad didn't bother you, chances are it was a good investment (probably). People who do get bothered by ads and their continuous manipulation use an ad blocker of course.