Joind.in is an open source project, which allows event attendees to add feedback for sessions they've seen at conferences. This provides valuable information for speakers (so they can improve) and conference organisers (so they can find out about speakers that they may not have met before) alike. It's a community project, and everyone is welcome to get involved.
Do something interesting with the joind.in API (http://api.joind.in)! We've been wishing for some javascript widgets for events and speakers to use on their own web pages, for example, but feel free to build anything you can imagine.
