Back in January I first saw this Robert Scoble interview with Guy Kawasaki, the startup guru. Now, I loved Guy's book (as does everyone else, btw) The Art of the Start, and after watching this interview, I was convinced by his "Twitter is a weapon" speech to try the service out myself. 
My main problem with Twitter thus far is twofold: 
1) It overlaps a lot with the facebook status update, which I totally love, and in fact works with it. However, the fact that it is wholly public causes me to bite my lip a little more and show restraint. This would be fine in theory, but the truth is that it's not really practical for me to both Twitter on the regular and maintain a healthy Facebook habit. Splitting my time between the two makes me feel less satisfied than before. Of course, this could simply be because I don't have critical mass of followers/friends (~40) on Twitter as I do on Facebook (~650);
 2) I don't like the URL compression that Twitter does. TinyURL.com, Bit.ly etc. clearly serve a purpose, however, I hate not being able to discern the link destination before I click on it. I want to know if I'm heading off to a random blog post, a flickr photo or a PDF file from NYTimes.com. The link address contains valuable information. I don't like not having that.

All that said, I'm still learning. Thoughts?