My BIL was a HR Manager for a Fortune 500 company. One of the first questions he asked was "Do you have a facebook account, and may I see it?"
You would not believe the things that people posted that had Masters degrees, and were going for 6 figure salaries.
There is no way I am going to give anyone access to my Facebook page. My reply to that is “my LinkedIn page is my public profile and I would be glad to share that with you.” My Facebook page is for family and close friends only.
I've heard that this is a very common HR question now, and that the applicants who do not have a Facebook account are not hired.