You know everything you hate about twitter? Downtime, walled garden, some very poor design in places, etc.
Identi.ca is a new open source project to build a better twitter. The actual open source project is called Laconi.ca, and it has been created by Evan Prodromou in Montreal who also founded Certifi.ca and Wikitravel (one of my favorite websites).
When you first see this project it is easy to write it off as a mere attempt to knock twitter off it’s throne, but I don’t see it that way. By releaseing Laconi.ca as an open-source project, Evan is betting (I think) on building out the sort of long-tail of microblogging. Charlottetown based SportsTwit is an example of niche microblogging that I think has a real chance of catching on (and should consider switching to the Laconi.ca platform).
The introduction of Laconi.ca brings microblogging from being a closed and proprietary world in to a more mass market tool in the same way that blogging is no longer just Blogger, but is instead a medium.
By using open standards like FOAF and others, different sites running Laconi.ca can talk to eachother and federate data. That means that if you are on a niche site, say startupnorth-tweets.com, you can interact with people on Identi.ca, and they have full access to your profile and other information. This is one of the core weaknesses of Twitter, its inability to federate out some of the load.
Good luck Evan, I have a feeling this is the start of something great, and a change that had to happen.
You can find me here: http://identi.ca/jevon