To collaborate more effectively with the NSA and CIA.

Credit checks.

Nowadays they offer financing for devices. But even in the past it was required. They would determine the maximum number of lines you had available, and if there were any deposits to open new lines of service. Even before phone financing, those phone contracts came with hundreds of dollars of phone discounts at time of purchase and had hundreds of dollars worth of early termination fees and they want to make sure their customers had a good chance of paying if they left.

Most people get suckered into signing a contract and using a "postpaid" plan, where you get the service for a month and then pay for it. That requires a credit check and credit reporting, since you get the service before payment. You don't have to give out your SSN if you sign up for "prepaid" cell phone plans, which offer less discounts and benefits but are generally cheaper for the service they provide. The only catch is you pay for the month before you use it, but this makes canceling as easy as stopping payment.

Antifraud

I think it's related maybe to some anti terrorism law? In certain EU countries for example it's impossible to get an anonymous SIM due to some anti terrorism legislation. SSNs are the only legal identification I guess?

This is a random guess off the top of my head. IANAL or know anything specific on US law.

To run credit checks and be in compliance with anti-terrorism regulations.

Let's evolve, let the chips fall where they may.

This is brilliant. The government could put out a searchable database.

Social Security Numbers were never meant to be used for anything other than Social Security itself. Credit agencies use the SSN because they view it as an easy identifier and they didn't have to create anything themselves.

But then I can't google my number when I forget.

I think the problem is there isn't any law protecting your data

086-07-5309

Hey, wait a minute! That one's mine, too!

I have your IP and your SSN

Hands up

Basically. It wasn't meant to act as an identification, but people kept using it that way (probably because every citizen gets one at birth, so it's the easiest proof of citizenship).

It's a key component. You need other information, but the SSN is supposed to be secret.

Getting names, emails, addresses, etc is pretty available. If you can link those up + an SSN you can open accounts pretty easily

Bill Gates has been trying for awhile.

SSNs are not secure and were never intended to be used that way. Just because companies misuse it for security to cut costs and apply credit ratings we never voted for doesn't mean we should necessarily punish someone for leaking that data that is already like 99% public data because of all the previous leaks. It would be better if everyone treated it as public data and not some secret identity key. They should be punished for poor security and fix their shit, but SSNs are not private, not intended to be used for identity, and not secure.