Even before the Social Security Number (SSN) was shown to be so easy to reverse engineer, I had been unenthusiastic about their ubiquitous use. For one thing, SSNs are the jackpot for identity thieves. Getting a victim's SSN is half the battle in faking her identity.
The security principle "need to know" applies here: only the people who can show a "need to know" an SSN should have it. If you don't have a datum, (say, someone's SSN) on your computers, then when (not if) the bad guys crack your computer, they can't get it from you.
I've just hit an example of an egregious use of SSNs. I just tried to create an account at the Wyoming Department of Workforce Services' wyomingatwork.com web site. The intake form wants a user name, a password, etc. All very standard so far. It also wants an SSN. The form doesn't say why they want it. As far as I can tell, the Department of Workforce Services has no "need to know" my SSN simply to open an account.
This is the first time in my half-century work career I've been asked for an SSN on a job site. By way of comparison, Monster.com's new account form has no such requirement.
I suspect a phone call and some pointed questions are in order. Sigh.