I love the domain. Perfect for a simple web app.
A few things:
1. I would move the 'About' tab over next to the 'Owed to You' tab. Stretching it across looks slightly off.
2. The last line of your copy could use a rewriting. Maybe "Try it out! Just use your own e-mail address."Or just take out the comma.
3. Is there a way to remove yourself from the e-mail list on the site? (not just in the e-mail.)