In my experience, Twitter belongs to the realm of the self-centered and egotistical. I just can't bring myself to do it. I signed up for it a long while back, but it makes me uncomfortable and I think it is a huge waste of our already limited time.
Brasse, I totally understand - that is exactly what I thought about Twitter - a playground for self absorbed twits who think the world is facinated to know they are having a latte at Starbucks! Then I finally looked into it and discovered that yeah, there are people like that, BUT I also was completely clueless about how lots of people are using it correctly. The idea is to contribute usefull stuff & build a good reputation. People will then come to you voluntarily because they value your contributions.
Anyway - read the free book and see if you don't change your mind!