what makes it work is that it doesn't actually impose work on you. you just click-off how you feel and keep doing emails. In aggregate, it's creating information that no one person has.
This is a tool aimed a dev teams but can be easily applied to sales, finance, or nearly any team. Especially helpful for remote teams or teams with little daily interaction to gauge where their heads are at on key objectives.
We've been using it for a couple of months now and think it's a great tool to stay on top of how the team is feeling and how the product is progressing.