Minsh. The Tweetsphere as an underwater virtual world
Minsh is an online world that is the brainchild of computer scientists working on the campus of the Federal Institute of Technology in Lausanne. The big idea is that the social behaviour of fish will represent what people are thinking and talking about online. In the world of Minsh, people writing about any given subject find themselves swimming in the same school. When a person updates his or her Twitter status, the fish swims away to join people with similar thoughts on their minds. Great!
Barbara Yersin, the co-founder:
"Minsh is an underwater virtual world where each fish represents a Twitter user, in reference to the phenomenally popular micro-blogging platform. So here, for instance, you have the fish of Al Gore, who is on Twitter and also on Minsh. He doesn't know it though."

An explanatory movie:
Currently still in a very early Alpha phase, the website promises the Alpha 2 will be released on July 13th 2009, with more features and just 1,000 invitations.
Via Infosthetics