A very simple, though useful, add-on. It would be much more beneficial, though, if there were a way to reset the timer for a particular project. In the current version, you can only add additional time, but because I keep a record of my daily productivity, this approach is limiting. My work-around is to delete and then add the project each day, which isn't very efficient. Otherwise, it's a great app.

About as simple as such an extension should be and it doesn't request to see all your data for all websites or require some bizzarre signup process.
For whatever reason though it is somewhat buggy on the first run.