This is a time-saving script I wrote to help me process my inbox faster. After 2 minutes spent on an email in your inbox, it pops up a reminder message to move on. (And when you have less than 30 seconds left, it shows a "30" icon in the browser bar to nudge you along.)
Great for quickly clearing your inbox for things like Getting Things Done (GTD.)
It's quite basic, but if you like it and use it, I'm happy to make improvements.
Update: Now you can choose how much time per email you want to spend.