I'm a vocal fan of Twitter, but I can appreciate that it's not for everybody. This thoughtful post by Benjamin Anastas clearly explains some very good reasons why he deleted his Twitter account* after making an effort to understand it:

...the whole thing is a boondoggle, at least it is for us. And by “us” I mean anyone who isn’t already a celebrity, a media star, an established brand, the literary equivalent of a laundry detergent. And even then I have a hard time seeing what being on Twitter gets you, other than the open and never-ending opportunity to waste a shitload of time you could be spending a lot more productively elsewhere. (Unless your personal assistant or your team of interns handles your Twitter feed, in which case I hope you’re enjoying your nice hot bath while the staff takes turns reading the daily blogs aloud to you.)

Joining Twitter doesn’t really make any sense for most writers. I mean, if you love it, go ahead. Keep Tweeting your heart out. You have a steelier one than I do. My friend A. was right when he said that you had to enjoy Twitter for it make any sense. But here is why I think joining Twitter actually works against the writer’s interests—starting with the obvious and moving on from there.

I don't agree with all of Anastas's complaints, but they're clear and they're well-stated and people who hate Twitter will find them very edifying to read.

* If I may digress—and I may—I would like to say that I don't understand the deal with Vine. I mean, I understand how Vine works, and there are even a few times that I'd likely use it myself, but I don't understand why millions of poorly edited amateur films are so appealing to so many people, including my coworkers. As members of this society, we all agree to traffic in words. But not everybody can be good at movies. And so I find it really hard to enjoy sifting through all these bad videos to find something amusing or interesting. I reserve the right to change my mind about Vine in the future, but I still haven't managed to understand the appeal.