[nsomniact]

I made a point earlier that the advertiser chooses the target audience and I don't believe FB does what this article claims. I've seen retargeting creep into FB lately but again someone is making assertions rather than an algorithm IMO. Some 3rd party ad networks let you really drill down.

I think FB can do what this article claims but is not actually doing it.

[Amadou]

I can't say what FB did here with much confidence - its an anecodte. But I'd like to point out that it isn't hard to reverse engineer the information out of FB. Buy a targeted ad and then watch the click-throughs. Cross reference the click-throughs from that ad with data from another tracker that knows identities and you've now been able to link whatever your FB ad criteria was to the identities of anyone who clicks through - even if they don't do anything else besides click through.