A client of ours sent a Facebook invite to a couple of coworkers. Neither of those coworkers have Facebook accounts. The invite was sent through email, and the bottom of the email contains as list of "People you might know". Indeed, most are people that the coworkers recognize, but they are not related to each other (many are clients). After a little thought, we realized that these were all people that had email correspondence with the coworker. This suggests that GoDaddy (our web site host and email provider) is sharing not only our email addresses, but the addresses of everyone we've emailed or received email from, with Facebook. As far as we know, they are sharing the entire email. I'm not a conspiracy theorist or privacy advocate, but doesn't that seem to cross a line? Can you think of another explanation? I've confirmed the email is legit and all appearances are that the list of names was compiled by Facebook, not by some code that ran in Outlook. Here is GoDaddy's Privacy Policy regarding third parties:

Third Party Service Providers

We may at times provide information about you to third parties to provide various services on our behalf, such as processing credit card payments, serving advertisements, conducting contests or surveys, performing analyses of our products or customer demographics, shipping of goods or services, and customer relationship management. We will only share information about you that is necessary for the third party to provide the requested service. These companies are prohibited from retaining, sharing, storing or using your personally identifiable information for any secondary purposes.

In the event that we use third party advertising companies to serve ads on our behalf, these companies may employ cookies and action tags (also known as single pixel gift or web beacons) to measure advertising effectiveness. Any information that these third parties collect via cookies and action tags is completely anonymous. If you would like more information about this practice and your choices, click here.