http://twister.net.co/
What is twister?
Twister is a microblogging peer-to-peer platform, that is, it is a distributed system like bittorrent or similar file sharing technologies. Being completely decentralized means that no one is able to shut it down, as there is no single point to attack. The system is also designed so it cannot be censored, freedom of speech cannot be taken from you. And because the cryptography is employed end-to-end, no entity is able to spy on your communications.
Is it open/free?
Yes. The protocol is open and community is invited to help to extend it with new features. The reference implementation is free software, based on Bitcoin and libtorrent sources, which are released under the terms of the MIT and BSD licenses, respectively.
How is Bitcoin used here?
Bitcoin, in the sense of the digital currency, is not used at all. However, the Bitcoin protocol and the implementation of the neat idea of block chain is on the basis of twister. The block chain provides a sort of distributed notary service, certifying who owns a given nickname. The name is associated with a specific key pair, which is used for authentication and cryptography.