Identi.ca vs Twitter

Popularity

• Twitter users count up to 190 million visitors per month.[1]
• Identi.ca (~70000 users[2])is very popular among software developer community and open source activists.

Technical plattform

• Identi.ca uses the OpenSource microblogging software StatusNet (formerly known as Laconica). It's like to Twitter what Diaspora wants to be to Facebook.
• Twitter uses its own proprietary software stack. The frontend is written in Ruby on Rails and the serverside messaging queue in Scala.

Features

• Twitter depends only on one provider and is monolithic, and because of this is often overloaded and slow. Because of StatusNet, Identi.ca can be federated with other, self administered by other providers and simple users, so it can cope better with very high traffic.
• StatusNet federated sites can exchange posts seamlessly between them and Identi.ca, so the overall network is really more stable and independent from a single provider.
• Both Twitter and Identi.ca support hashtags to tag posts (useful for searches).
• Twitter totally misses the !group feature of Identi.ca. On Identi.ca you can follow groups, usually about specific topics, and this make it easier to know news about a topic and find people with your same interests.
• Identi.ca lets you see a post in its context, with all the replies, so it's easier to follow discussions between users, and because of this discussions in Identi.ca can be quite long, sometimes. Since Twitter misses this feature, discussions in Twitter are usually quite short.
• If you need to be present in both microblogging platforms, you can connect you Identi.ca accout with your Twitter one, making Identi.ca posting automatically to your Twitter account.