This is not the first time the folks at Facebook have needed guidance.
And, thanks to the effort of the Electronic Privacy Information Center, they'll be given another lesson. http://epic.org/privacy/ftc/facebook/Facebook-Study-Complaint.pdf .
That lesson is: If you are unable to make wise decisions regarding your interactions with others, others will make the decisions for you.
Those hundreds of thousands of people have the right to be notified that they were subjects of this study and then they have the right to decide if they want to initiate a class action law suit.