Let me kick in some open doors here.
(I've slept three hours. So I get to be obvious)
Much as I am a relatively late adopter, I like Twitter. I like how, unlike the Facebook of Doom, it is simple and usable (reservations about restrictions on third party apps aside). Not that I tweet much. To quote @_snape_
"You think I'm not online. But I'm always here. Even if I'm not tweeting. I'm here. Scrolling. Judging"
Most of all, I like that it allows me to:
a) be a nerd in a pretty nerdy space - to talk work and tech and silly small discoveries
b) be amused, enlightened, or both
c) give direct feedback to people
That latter one is 99% an opportunity to tell some mildly famous person that I like something they did. I like that it gives me an opportunity to err on the side of complimenting and thanking people without invading their space (I've talked before about how I terribly timid I am about approaching people in the flesh, and how I am always worried about being disrespectful when I am trying to be the opposite).
I like that it gives me a low stakes opportunity to be nice. The judging is just a bonus.
*Yes, nerdy reference to One Epic Knight