What can you find by knowing someone's SSN?

[zap0paz]

The title says the question itself. Can an employer find previous workplace/s by checking your SSN? What else can be found by checking your SSN?

P.S. Why do businesses usually require you to put your SSN when applying for a job?

Thanks beforehand!

 

[Concerned4us]

Credit and/or criminal background check.

 

[topuser]

you can do it a lot of things... maybe you can duplicate an account or credit card... anyway in the underground industry, they can use it in many ways