Aro looks pretty interesting, and obviously, as a fan of algorithms (especially those that intelligently mine your email), I’m intrigued.
TechCrunch has some invites, just fill out the survey for a shot at private beta access.
I’m cautiously optimistic about Aro’s possibilities, but a bit skittish about the security aspects. I’m expecting to see OAuth for Google access, but for the Exchange stuff, how can they handle that securely?
Anyway, algorithms are the future (ahem, Pedrazzi), not self-organization. Wait a few months and see what a fail Facebook groups are.