....just watch videos or get interactive, so to speak, with the content. What I mean is, when watching an Australian car crash video, I saw a building that says, "Harry the Hirer", so I Google it to see what that's about. Same with the coordinates on the dash cam, put it in Google maps and pan around the street where the crash took place. Or when you see a numberplate, I sometimes put it through the government website to see if it's taxed, mot, and what brand of car it is. If you do interact with YouTube, I'm all ears for other creepy tips.
Probably only rarely. This doesn't even sound like a political question. Probably belongs in "other off-topic chat".
I might comment on a video. I'm sure on occasion I've looked up something I saw and wanted more info about but I can't recall anything specific. Most times I'm not even logged in when using it. And more often than not, the only thing that gets me to log on is to upvote a comment someone else wrote. And even then, the amount of times I even look at the comments at all is not high.