Formspring is nice because it's not real time. It sucks because following a conversational thread is somewhere between difficult and impossible, and it's hard to log.

IRC is real time, and it's difficult to follow threads. It's also difficult to tell who you are at a given moment.

If we're really going to do this, a community is probably the way to go. Most of us should have at least a couple of DW codes by now, and it's much easier to follow the back and forth of a conversation and to edit logs into fic.