Looks interesting, good design, didn't try it because it requires a login that gives a scary "THIS APPLICATION WANTS TO READ YOUR EMAIL ON GMAIL OH NOOOEESSSSS" login.
Huh?
I actually use the App Engine Users API and zed I'm truly sorry for the crappy message that put you off.
What it meant was that the application would have access to see your email address i.e. google will disclose the address zed's-id@gmail.com
Unfortunately that's the default minimum permission set granted. I use it to send people a welcome message. Further, I promise not to be evil here:
iheartpy.com/privacy.txt