But does a reality check on the claim: "Facebook gets a report every time you visit a site with a Facebook 'Like' button, even if you never click the button, are not a Facebook user, or are not logged in."

"Even if you have restricted your information to be seen by friends only, a friend who is using a Facebook app could allow your data to be transferred to a third party without your knowledge," writes.

That information includes visits to pages about health conditions or treatments, which would interest insurers; announcements about attending an event, which would interest burglars; and information about sexual, religious and racial/ethnic affiliations, intimate relationships and even drug use, which would interest potential employers.

's Dan Tynan on how many of the more than 500,000 games, puzzles and quizzes on Facebook exist mainly for the purpose of, "sucking data out of your account."

Some of those apps violate Facebook policies, but Tynan notes that the enforcement of those policies can be lax, at best. And while there is now a that rates how each app treats your data, that score is largely based on the policies published by the apps and tracking companies, which can also have credibility problems.