An ad blocker is a software product that prevents advertisements from appearing with the content the user is intentionally viewing. People block ads for a variety of reasons. For example, many of them find interrupt marketing ads annoying and even stressful. Interrupt marketing is intrusive by design, like an interstitial ad that comes between users and the content they are attempting to view or an autoplay or rollover ad that starts up without any intentional act on the part of the user.