Although the details might not have been predictable, it should come as no surprise that Facebook did to consumer what they're alleged to have done. See Facebook Added 'Research' To User Agreement 4 Months After Emotion Manipulation Study.
The movie The Social Network told us a lot. An interview aired on some radio program with the guy who wrote the book which supplied the story for the movie. The author used transcripts from depositions from the lawsuit in which one betrayed friend and two betrayed business associates sought recovery for their share of the Facebook business. Since live people were involved in a litigated dispute, the author had to be careful to stick very closely to the testimony in the depositions. The movie did too.
So while it is never a good idea to base one's belief in historical events on the movies, "The Social Network" might be as close to an exception as we can get.
In any event, someone who treats his friends and associates the way the character in the movie did is not a friend. That so many people trusted him and his company with their most personal information doesn't speak well of the level of critical thinking that exists in modern consumers.
Meanwhile, the above linked Forbes.com article contains another tidbit. To wit:
Defenders of the Facebook study including my colleague Jeff Bercovici say that everyone on the Internet is doing A/B testing — showing users two versions of something to see which resonates more based on how they click, share, and respond.
Quite so. Yahoo mail users see a completely different lineup of news items after they shut down cookie acceptance. Surely they're using some program that figured out what might keep the user on the yahoo site.