ThinkUp is the first free app that lets you to archive your Twitter, Facebook, and Google+ activity, a powerful open-source tool for analyzing and searching through the activity of your social networks.
A sample of ThinkUp's features:
Archive your Twitter, Facebook, and Google+ history
Get an at-a-glance overview of your network activity from ThinkUp's dashboard
Search and export your complete post history and post replies
Track your follower growth over time
Geocode replies and visualize them on an interactive map
Publish and embed conversations on your blog or website