This seems like it will suffer the same problem as Loopt and other location aware iPhone apps: you have to open the app to update your location.

Also, the way this works is Newber gives you a special phone number that people are supposed to call, and it routes it to whatever phone you want. You can then transfer the call between phones by hitting a button in Newber. This is fine for incoming calls, but what about outgoing calls? Do they have a way to intercept outgoing calls from yours phones or something?

I did like how the dude's business card said "Professional Silhouette" though.