Finally an iPhone app that shrinks your data usage and thus, your bills.

And how the hell is this supposed to work, exactly?

edit: Ah, it's just a proxy. From their FAQ:

"How does Onavo work?

With Onavo installed, web, email and app data sent to you is streamed through Onavo's magical shrinking machine before reaching your iPhone. For the geeks out there, what happens is that Onavo acts as a proxy server for your iPhone, which compresses inbound data to Safari, Mail, Facebook, Google Maps, Twitter (currently only TweetDeck and EchoFon) and other apps."

This is disruptive tech. Security looks to be one concern but this is a must buy for Apple!