Lori Andrews:

The term Weblining describes the practice of denying people opportunities based on their digital selves. You might be refused health insurance based on a Google search you did about a medical condition. You might be shown a credit card with a lower credit limit, not because of your credit history, but because of your race, sex or ZIP code or the types of Web sites you visit.

If you use Google, or any social network, then this is a must read.