(EDIT - Why would you downvote me for answering his question? Someone explain why twitter is such an amazing tool that I should incorporate it into my already busy life...)
I was also very skeptical, but finally I found one good use for Twitter.
If there is some real-time trouble (e.g. you couldn't access your Gmail account, or Hacker News), Twitter is the first place where you can confirm your suspicions (and sometimes even find a solution/explanation).
On Twitter you can find out in minutes if there is anybody else having the same trouble as you, instead of hours till Google indexes blogs with complaints.
Searching Twitter is now my default reaction to figure out what's going on:
I have had quite a few opportunities b/c of twitter. I will be speaking at GlueCon in Denver b/c of Twitter. I am much more deeply connected to my local tech community b/c of Twitter. And there are friends that I have a deeper relationship with b/c of Twitter.
Now, having said that, there is absolutely no reason anyone should have down voted you for answering the question.
Do you need it? No.
Can it be highly beneficial? Yes.
(EDIT - Why would you downvote me for answering his question? Someone explain why twitter is such an amazing tool that I should incorporate it into my already busy life...)