you are right it's not on the same scale, but it's exactly the same idea on a small scale. Users are anonymous (if they want to be), they can spout loads of drivel/their opinions for other people to read, can cause offence, can be rude, racist and so on. Or like the majority of users on twitter and facebook they can be perfectly nice human beings, considerate and not deliberately provocative.
It's just a matter of size.
none of us have millions of followers (on here) but for example yesterday you wrote "I'm back, did you miss me" like you were expecting people to have followed that you weren't here. So you DO have followers (or at least expect to)
I honestly can't see any difference to Twitter/Facebook