I was never a big Tweeter, but found the concept strangely compelling. There are many people ranting on the web about service disruptions, but I never used it enough to be troubled.
Nevertheless, I like to try new things and stumbled across Identi.ca yesterday and set up an account with the short, early-adopter user name of mjg.
The service is Open Source and I like the fact I can login with openID. There is the promise of things to come in terms of integration and updates, such as SMS, Facebook and WordPress.
There is a good in-depth discussion here.
These articles might be of interest:
