Reposting was just the beginning. Much like Twitter with their @-replies @-mentions and #-hashtags we wanted to see what sort of usage pattern would emerge organically.
We're now working on a pretty big new feature called "branching" which I'm excited about because it actually solves quite a few issues (including comments, conversations, tangents and a bunch of other stuff) in an elegant way that mostly follows the existing conceptual basis of TS (which we're trying to keep simple).