That's the problem with the social security number. We've become so scared of using the SSN, the number has become useless. What we need is a unique public ID that we are not afraid of using. In my ideal world, we would all have a public and private ID. With someone's public ID I could use it to call them, text them, IM them, email them even send them postal mail by simply writing their ID number on the envelope and the post office's computers will know how to route the mail. People would use their private ID to log onto some central server to set the places that the public ID points to as well as block certain users and deal with privacy restrictions.
You could use your public and private ID to log onto all your services so you don't need to keep separate accounts on various webpages. Both Northwestern and the University of Chicago have single electronic IDs and passwords to access email, benefits and wage information, course information, get wifi access and much more.
Now that people avoid using the SSN as a public ID, cell phone numbers and email addresses are beginning to play that role. Privacy advocates have slowed down efforts to have a public ID for a variety of reasons. But the great need for an ID means the market will start using whatever it has available and isn't it better to carefully design a proper public/private ID than have some ad-hoc market-driven system instead.