This is false. Ads are targetted based on the website, mainly. You'll find gaming ads on gaming websites.
Why do we sometimes get dating links from hot Russian girls or something like that then lol? This isn't a website where you'll find a hot Russian girl
1. Get an AdBlocker. If cyp wanted to, which he won't lol, he could upgrade the forums so there is no ad's. Plus the ad's are apart of your history.
A lot of ads are based on your searches, say if I went on an online clothing store, an ad for that store will come up eventually. I recommend getting an adblocker or finding a way to not be tracked when browsing, I believe some browsers have this feature.
Ads and how they're shown is a rather complicated system that would take me far too long to explain over text. Ads are based on a lot of different factors that factor in the website, the type of website, a number of times a particular ad is clicked, content, general market, random chance, and a lot of other variables. For example, I get a lot, and I mean a lot, of ads about single Asian girls. I have never once searched that nor have I search for anything regarding it. However, other people with similar browsing habits to me have. Porn is supposedly common with gamers and, let's not forget, a large amount of the internet is filled with porn. 18+ ads aren't uncommon. Example: Every player on Skyblock, except for one, decides to search 'free music' and it became a trend, everyone would get ads targeting that. Yes, your search history can play a part in how ads are shown, but it's not reliable. tl;dr: Just because someone has an ad about a sex game, doesn't mean they search for it. This is a game, and most gamers search for 'sex' and/or 'porn'. P.S: It also depends on what ad manager a website uses and what the settings are.