Twitter has just taken a step toward a richer social experience with its exciting new "lists" feature, which gives users the ability to organize individual accounts into groups. For example, a user can create and share a list of "celebrity" accounts that they follow. Twitter lists may be marked by their creators as public, or kept private for personal use.
Socialmod is a system to either automate or simplify your site's social content moderation. Its socialmod API allows for direct integration of socialmod into your site, making using their service far easier. Its service has been used for such high-profile sites as the BET.com awards, as described in its blog.