OpenMicroBlogger actually has been released in 2009, but maybe some of you don’t know about this free Microblogging platform. OpenMicroBlogger is developed by Automattic, which also develops WordPress. Many people say that OpenMicroBlogger is a Twitter clone. It’s true, I think. 
Look at these screenshots :
According to several reviews, OpenMicroBlogger get a positive response, see review on ReadWriteWeb and Wired, they provide a good review of OpenMicroBlogger.
You can try OpenMicroBlogger, and please give your own score.
Or you can try to install it on your own server, download the source.
