I've created a proof-of-concept of a 'twitter on the blockchain' utilizing the SysCoin Blockchain.
For it's not going down in the discussions here, I created a new thread for that:
SYYK - Messaging on the blockchainWow. That is pretty slick. I will pm you an advert "systweet" as soon as I get
http://syscoin.market up and running with a web store.