This is called data enrichment. It is a massive industry with boatloads of companies serving it. One of the more well known (outside of the credit bureaus) is A

This is called data enrichment. It is a massive industry with boatloads of companies serving it. One of the more well known (outside of the credit bureaus) is Acxiom. Googling will get you pretty far. If you have money and a piece of personal info (just about any combo of name+zip, phone#, email addrs, credit card, tracking cookie, etc), these companies can quickly give you full personal details including income and housing history, mortgage status, email addresses used, employment history and full details on your employers, plus all these details on spouses and children, pretty much whatever you want. It's remarkable.