Twitter obviously has flaws:

1. It hasn’t announced a business model yet and people are afraid its introduction will break the utility.
2. It suffers from many well-documented technical interruptions.
3. You can’t segment your “tribes”, allowing you to improve the signal-to-noise ratio, as you start following more people.
4. Most of my (and possibly your) contacts are not on Twitter yet, which reduces its intrinsic value.
5. It’s a huge time-waster, looking at the conversation feed and making sense of it all.