> So if everybody knows your SSN/DOB, I'd say that makes a very good identity system in the sense that we can all unambiguously refer to the same person. If th

> So if everybody knows your SSN/DOB, I'd say that makes a very good identity system in the sense that we can all unambiguously refer to the same person. If that was all it (SSN) was used for, a "unique-id", it would work ok for that usage. The problem is that far too many companies also make use of SSN as a "secret only you know" to authenticate that you are in fact the individual identified by the SSN. I.e, your "login name" is identical to your "password". It is this miss-use that leads to the problems around SSNs.