This Widget shows a graphical history of the IM status of your iChat buddies. Choose to keep a 5 hour, 10 hour, or truly obnoxious 24 hour graph on your screen. As the hours pass, the bars on the graph slide to the left, so the most recent data is always at the right-hand side.

Bonus function: You can also leave 'frozen messages' for buddies who are offline. The messages are delivered through IM as soon as the buddy becomes available.