2011/11/26 Raj Mathur (राज माथुर) raju@linux-delhi.org:
SSN is just that: needed for social security. If you're Gill Bates, you don't need an SSN since it's unlikely you'll ever be on the dole. It's not mandatory.
Not sure how did you get that impression. For example, you can not even get a post-paid cell phone or credit card without SSN.
SSN was not created for this purpose, but in absence of national ID it has become a de-facto national ID.