A lot of businesses don't even bother having websites anymore; they just use Facebook.
Facebook jumped the proverbial shark once it was commandeered by businesses using it as a promotional tool. And I'm inluding pretty much everything here, from bands and movies, celebrities, restaurants etc
It took what was once a cool, hip little site and transformed it into a giant corporate weapon of THE MAN desperate for as many 'Likes' as they can get their grubby little hands on.
You're right in that you can avoid the majority of that by using it sensibly but I don't blame kids for thinking that what was once 'theirs' has been taken away from them by joyless suited douchebags.
This is my biggest gripe with facebook. I should have known it was inevitable in retrospect, but the facebook I joined is significantly different from the Facebook as it is now.