Well twitter suits the sort of journalists who are lazy. They dont even have to call anyone to get a quote or confirm something, the stories almost write themselves, perfect.
It suits some famous people too, they dont have to cultivate a relationship with a trusted journalist who will convey their side of the story without twisting their words too much. Now the famous can cut out the middle man and misrepresent themselves!
In some ways twitter is what you make of it. I can have a very different twitter experience compared to the sort of negative hellhole that is usually evoked when twitter is mentioned. It just depends who you follow and what sorts of things those people are interested in tweeting about. In my case that means my twitter feeds is mostly full of strange pictures and people talking about computer graphics programming.