The exact features of this applet have yet to be determined, but it will generally provide a means to track how much time you spent per task.
Overall you should be able to add tasks or task categories, and then simply start recording or logging time to these. This way you can later compute statistics that give you insight to how you work and help you plan better.
In addition we could automate some of the tracking with extra OS integration. It could do additional application tracking and website tracking in order to help track productivity.