I've only been using Twitter for a few weeks, but I'm already finding that I kind of miss it when it's down. And it's been down all night as far as I can tell.
The funny thing is that my first impulse upon waking up this morning and finding out that Twitter was down was to send out a Tweet about it. Generally I tweet about all sorts of things that I normally wouldn't devote a blog post to. It's amazing how addictive sending out 140 character or less messages can be. The instant feedback you get by using a desktop Twitter client like Snitter or Twhirl also makes Twitter a bit more attractive. It's kind of like engaging in a group chat with a bunch of folks that you may or may not know.
Anyway, it's down right now. I kind of miss it. On the one hand, Twitter offers a nice distraction from work at times. On the other, it actually often helps my work as a blogger, since the folks I follow often post interesting links and discussions. If Twitter ever goes online again, you can follow me by clicking this link.