From BusinessWeek:
Search engines make it possible for employers to scour all manner of digital dirt to vet employees.
Googling people is a way for bosses and headhunters to do continuous and stealthy background checks on employees, no disclosure required.
Google is an end run around discrimination laws, inasmuch as employers can find out all manner of information - some of it for a nominal fee - that is legally off limits in interviews: your age, your martial status, the value of your house (along with an aerial photograph of it), the average net worth of your neighbors, fraternity pranks, stuff you wrote in college, liens, bankruptcies, political affiliations, and the names and ages of your children.
