My children use it to get updates from businesses (who often tweet sales and specials), from organizations that are sponsoring events, to get observations from Adam Baldwin, etc etc. They don't use it to communicate with friends or psuedo friends or celebrities.
I like to jump on it and add my 2 cents when there's a tread going that's bashing Obama and his stupidity.
At the stand up for religious freedom rally I went to recently one of the speakers ask anyone with a smartphone and twitter account to live tweet the event. He said the media pays attention to such things.