This is where phone numbers can come in. Phones as unique user identifier Phone numbers are ubiquitous and people generally retain the same number for a long period of time, e.g. a decade or more.

Jangl is a very weird and potentially very useful service that assigns unique phone numbers to relationships. To get the Jangl number to reach me, for example, ...

Fancy number plates and phone numbers are always in high demand and some people push their boundaries to own them. Recently, Dubai's latest charity auction of 'The Most Noble Numbers' saw a unique ...