Ethical considerations aside, this seems like a solid management strategy to me. They have the brand to push through large mass of users , who are not so much into gaming as they are into socializing. If I were an investor in Zynga, I would be very happy , although I would probably use a part of the 10x ROI to buy a sweet gaming rig and play real games.
I don't know anything about this, so I'm just speculating:
Are they into socializing? Or are they just into a pleasant distraction that fires off addicting dopamine patterns that they can also share with their peers?