Like ququoo.com, I see Twittergram front-ends existing on-top-of, but for all intents and purposes independent from Twitter.com proper – using Twitter’s infrastructure for authentication, messaging, but otherwise very distinctive from Twitter as it has stabilized. The above sketch is heavily inspired by Twitterific, which is an OK fit. Something is still missing from it though.
I’ve got a couple *cast domain names that have been waiting for something like this. 🙂
28 Jun 07 Update: This is idea coming along. The mechanics of about 50% of the sketch’s functionality are in place. The next 50 is where it gets interesting.
30 Jun 07 Update: Started building out the interface. Not happy with how it coming along. It shouldn’t be this hard.