I credit Leo Laporte with introducing me to Twitter. It was Leo, Alex Lindsay, and Merlin Mann that showed me that there was something more to Twitter than it just being a "silly little thing" that I thought it was at first.
But, now Leo has left Twitter due to trademark concerns. He has started up a Jaiku account and is now singing its praises. I got myself a Jaiku account and looked around it for a while. I don't like it. Actually, I really don't like it. They have a lot more features, which is kinda cool. They tried to keep the interface simple like Twitter had done but with all of the features they added the interface just ends up REALLY confusing. Plus half of those features go too far and make Jaiku into something more like a Tumblelog which is far more than I want or need. The main reason that I love Twitter is that it does one thing really well, not a dozen things half-assed.
So, in conclusion, I'm sticking with Twitter. Leo, I understand that you need to defend your trademark but you didn't need to leave Twitter to do that.