So far, targeted ads don't really seem to work that well (studies have found). I don't think getting the size of my rooms will be that much of an improvement. They can infer maybe how much money I have, but they can probably already guess that from my address and my credit card company also knows. It's not even clear that the data about my rooms is transferred to Facebook.

I don't think making better targeted ads is the play here. I think they want to dominate social networking, and they think a lot of social networking will take place in VR in the future.