[orclev]

Social security numbers are most emphatically not identification. The social security department tried for many years to get people to stop using your social as a form of identification, but companies (and sometimes even the government) still keep doing it. Social security cards printed before 1972 actually had a disclaimer printed on them that said "Not for identification purposes", but the message has since been removed. Although rare, there are actually duplicate social security numbers as well, and not everyone has a social security number. A number of religious groups, most notably some sects of Amish, refuse to get social security numbers and regularly fight legal cases to prevent having a social security number as a requirement for access to government services (although obviously not social security).

[T-hawk]

Popular misconception here: That disclaimer meant possession of the card is not identification, since it doesn't have any verification like a photo. The number does represent identification, as far back as 1943.

Source, the Straight Dope: http://www.straightdope.com/columns/read/141/why-does-my-old...

The SS card is a name-to-number mapping once the name is already identified by another document like a driver's license or passport.

[josephlord]

The US seems to have this quite backwards. They should be identifiers NOT authentictors although it is always likely to be slightly messy as some people won't have one and others may end up with multiple but having multiple people with the same number sounds pretty wrong.

[ajre]

Well that's interesting... Thanks for debunking my notion of SSN as an identifier. Sounds like a problem that needs to be solved.

[masklinn]

It could be solved as pretty much every other country on the planet does it, with a national ID number (& card). But the US population rises up in outrage every time this is suggested.

[yen223]

My country's government has done a lot of idiotic things, but I don't believe that instituting a national identification system is one of them.