Over the weekend, Google admitted it used private information about Facebook users to target advertising, AllFacebook reports. Google sells advertising to Facebook application developers, which Facebook permits. Google's mistake was "allowing" these developers to redirect information from user profiles through Google's AdSense system in order to serve relevant advertising. That's a violation of Facebook's terms of service. The irony?

Facebook does the same thing, of course. A couple of weeks ago CEO Mark Zuckerberg called it behavioral targeting and said it would change media for 100 years to the near-unanimous praise of Madison Avenue advertising agencies. It's not that Facebook disapproves of targeting ads to its users' private data. It just disapproves of Google doing it.

Contact information for this author is not available.