"Your phone number is your identity" for mobile-only social networking app: ------------ eMail followed the postal communication mechansim. eMail and eMail groups are push from the sender. Chats continued this. eg:WhatsApp
Where as social networking websites (such as Facebook, Google plus) are pull mechanisms. Speakers keeps speaking/sharing his content. It is the receiver who want to pull or not.
I want to see a social networking website that is "Mobile only" and the receiver does not need to know the sender's id (say username) but just phone number.
So one should be able to follow the sender/speaker just by knowing the sender/speaker's number (similar mechanism of facebook or google plus for following)