From what I read about it, Twitter is for no brainers who can't write sentences that are more than what, 20 words long ? Not even talking about a structured text, of course.
As for Facebook, it's for people who try to make their lives look interesting, and try to believe they have friends.
I don't even have a twitter account. As for Facebook, I "overused" it so much I forgot the damn password.
Steam could be OK I guess, but so far, it is a totally unorganized mess of a "forum" compared to the one here.
I am so old fashioned, you know, believing an official forum would be the main place to share official informations. Silly me.