Facebook Messenger allows sign-ups with just a name and phone number
 

Facebook Messenger might as well be as ubiquitous as SMS text messaging for some, but there's a catch to getting everyone to agree: despite there being over a billion Facebook users, not everyone is able (or willing) to fire up a social networking profile to get started. Some of the Android users among us won't have to go through that trouble as of today. An imminent update to the Facebook Messenger app will let anyone sign up using just their name and a phone number; any initial friends will come directly from the newcomer's own mobile contact list. The rollout is currently focusing on Australia, India, Indonesia, South Africa and Venezuela, but should spread to the rest of the world in short order. iOS users are also in line to get the update, although the timetable is less definite. Whatever the platform, Facebook is clearly eager to give those seemingly few holdouts from its service an easy way to test the waters -- and possibly save on their messaging rates in the process.

http://www.engadget.com/2012/12/04/f...me-and-number/