> That + the fact that it was tied to your phone number was in my opinion genius. This is an important aspect. Having accounts and contacts based on phone numb

> That + the fact that it was tied to your phone number was in my opinion genius. This is an important aspect. Having accounts and contacts based on phone numbers allowed my mother and her friends to use the service in no time - those are the kind of people that don't know their own email address (if they have one at all) and would never register for an account on their own. Phone numbers, however, is the system they already knew since using SMS.