I'm on there a lot at work between customers. I like the AMA, AskReddit, and TIL (Today I Learned) stuff.
The AMA's (Ask Me Anything) are probably my favorite. Really interesting stuff, from celebrities, down to people who are or have been homeless, just answering questions and telling their stories.
There was one on there the other day from someone who's been teaching english in South Korea for a few years, which is something my brother in law is considering.