First off, love the site! Great design, good functionality; It's awesome! I sent in feedback a few weeks ago about having more than one active session and that's already been implemented. Thank you and great job!
A lot of people don't seem to be bothering to add avatars to their profiles.Have you considered integrating with Gravatar, or a similar solution, to pull avatars that people have configured elsewhere? It could help liven up the comments sections a bit.
Keep up the awesome work!