Sorry missed the followup comments.
Google is the matrix, that's how they find out! There are many ways they find out, and mostly automatic. They might ban hammer a porn site, which has an ip address and url - and the "googlebot" may trace that url around and see what other sites it is linking to, or is linking to it. Using that method alone it is not hard for the googlebot to find a porn thread or "racy content" thread. Advertisers through the Google Adsense program (and google as well) don't want their ads showing on sites that promote / contain porn, that's the easiest explanation. I rely on those ad dollars to help run this site.
That said, I just prefer not to have "it" on this site. I surf from work and a butt ton of others do as well. I have many times been scrolling a thread and then BOOM "it" appears on my screen, or some chick in slo-mo with ta-ta's a shakin'. What do you know, co-worker #7 walks past and sees it and starts busting my chops thinking I'm surfing "that" kind of site. Great...
So, it's things like that - this is a metal/music (and related) site. Sure, there's a social area and there are plenty of off-topic areas, but as long as they are just words on a screen vs. tits and ass galore, people walking by don't stop to read words - but T&A jump out pretty easy. I'm as horny as the next dude, happily married for coming up on 20 years - but there's a time and place for all that and I think majority of us here would prefer it is not present on this site so we can relax while surfing around the site.
As far as the Youtube stuff - can you show me some examples of threads where it's becoming annoying?
