Dugg Analytics: Rich visualizations, metrics, and stats for Digg. Get charts by category, user, and time.
Zuckerbucks: Zuckerbucks are points that you can use like play money on Facebook. They have no cash value, but you can send them to friends as gifts, or as payment. You can also bid on real products featured within the Zuckerbucks app.
Jaikuvision: Mashup of Jaiku and Google Maps. See what different people are doing and saying around the world.