What Twitter needs are “channels.” A channel would be something that each person would get 36 of, each designated by a character (0..9, a..z) and then they could tag each of them with a name like “family” or “drupal.”

Once someone turns on channels in their Twitter account they would begin their tweet with “{channel}:”, i.e. “a:Has anyone seen my car keys?” where channel “a:” is only members of their immediate family, and “b:What’s the best way to get video into Drupal?” where “b:” includes people who share experience in Drupal, and so on.

A person would give set each channel to be either “open-to-join” or “invitation-only”, and would also it each channel to be either “public” or “private.” Twitter could then aggregate the tweets (i.e. all “drupal” tweets) and serve relevant ads on the pages that display them.

Twitter could also host global channels (i.e. such as a global “drupal” channel) where anyone interested in drupal could join it, associate a character with it, and tweet into it (like a IM-based mailing list.)

With channels as a base infrastructure it would be easy to implement all your “killer features” mentioned above.

If Twitter would implement channels as I’ve described, I would actually use it. Until then, it’s just a waste of time for people with too much time on their hands.

P.S. If they DO get the idea from me and then implement it, they really should give me some stock options…