It used to be that YouTube would just recommend stuff without telling you why, but now it links each recommended video with something you watched. And if I was watching Nick Cave videos last night and it suggests an interview with him, that makes sense. But some of them are just nuts, like this one:
Miley Cyrus - Party in the U.S.A. Because you watched Keanu Reeves is immortal
Wait, what? How does that even follow?
If you've got an account on YouTube, sign in, surf a bit, and then go to the homepage and see what it tells you. Sometimes you'll find some interesting new stuff, but other times it's just bizarre.