RE: Why it's easier today for a thief to guess your nine digits
1) The SS# is mighty convenient as an identifier - just like ones name only unambiguous. The id theft problem is not because one has this unique identifier, but because financial concerns use it for purposes for which it ill-suited - i.e. giving out money. The cure is not to hide SS# but to use other / additional identification for financial matters.
2) We must be close to running out of 9 digit SS#s - 1/3 of them are currently assigned to living individuals, probably another 1/3 to expired folks, and 1/3 for business taxpayer id's.
I thought that there were already SS area numbers that had been exhausted and that the number scheme: area-group-serial had been superceded - much in the way that 'phone numbers became more random as area codes were exhausted.
Have you heard of extensions to SS# lengths? Imagine what a transition from 9 digit to even 10 digit SS# would mean ... shades of Y2K.