This is actually not like twitter at all. It's a real time group chat. What I like about it is the great versatility of the app, you can use it as a collaboration tool, or to start a roleplaying game with some friends, or to publish your status, or as a fotolog, videolog, microblog, name-it-blog, or just to be in contact with your friends and have some fun. It's actually more like googlewave, but more streamlined. One more thing worth mentioning – it's an opensource rails app hosted on github, so anyone can contribute ideas, or even run it on their own.