Are you tweeting today?

Since Twitter has been in the news a lot, I am trying to figure out the purpose of it. I know some people cannot live without their twitter, but it seems a bit over the top for me. Obviously, since I haven't been able to even blog for about 3 weeks, I do not have the time to tweet hourly or daily as most people do. So, is there a different purpose to tweeting that makes it worth it? Am I missing something about the whole Twitter experience? Even if I had the time, I am not sure I'd want that much of my knowledge out there and open to the world? Can anyone offer anything about Twitter that I may be missing? THANKS!