The absolutely simple yet clever idea is that you can easily separate your friends into groups and this makes Rally Up more interesting to me then Foursquare and Gowalla. Here are your options:

- Real friends: These are people that you want to know everything about. Their activities will appear in your feed and trigger push notifications.

- Feed friends: You’ll get updates from these individuals in your feed, but you won’t get push notifications.

- Lurk: This lets you see what your friend is doing but won’t let your friend see where you are checking in.

- Mute: This category is for those guys who ad you everywhere and you are just too polite to refuse them. You won't get any notifications from them and your status will not appear in their feed.

Besides that, i really like the GUI. It's simple and appealing. Alas, as nobody uses Rally Up yet it is still more or less useless. Maybe all you iPhone users want to join? Now?

Actually I don't like this ad and I definitely think that it won't go viral. Nevertheless the stats are interesting.

Please notice:
1) Most users drop their account after a month.
2) 1/3 of tweets is pointless babble.
3) Over 40% have never updated their status.

btw: Thanks Mashable!