So far I haven't really caught the Twitter bug. I'm not interested in constantly updating my status or following other people's daily minutia. I'm not interested in participating in promotional contests for free t-shirts and the like. If I want to check the news, I look at RSS feeds (which generally are better suited for that purpose) using my computer or cell phone. I did read some feeds during the Iranian protests, and I read a
Girl Genius side story that was posted in installments on Twitter (feed
here, archive of early segments of the story
here).
(Incidentally, does anyone ever get confused, while reading the word "read", as to whether to read it in the present tense or past tense? I can't recall being confused by it on any particular occasion, so I guess the tense is usually fairly clear from the context, but writing the last sentence of the previous paragraph got me thinking about it. Maybe my mind is just wandering because I didn't get enough sleep last night. :P)
Also, while it may be true that many meaningful things can be written with 140 characters, it's still a severe limitation, because quite a few things are not
best said in installments of 140 characters or less.
Perhaps other people find it useful, but I don't anticipate becoming a big user of it in the immediate future.