i believe that these exist on mobile games only (based on my experience), they aren't that fun of thing at all, especially when your volume is high, then some ad pops up, it's really annoying and some games ask you to pay to get them removed, if it's a matter of few bucks, and you really love the game, then it shouldn't be a big deal, but some of them don't have that option and those ads keep happening again and again, one more reason to not play mobile games :(