True, but this is at least partially developed and Facebook isn't creating something completely new, although integrating the technology into FB might be the "developing". This might be more like the 10 store strip mall being turned into the Mall of America. FB is paying the full price for Mall of America just to get the revenue of a family run property.
I don't see how they can increase the revenue 100x or more (using the real estate metaphor) as I'm guessing the data mining from that would overlap their current business. My current ability is only getting 10-20x on CD, DVD, and toys; and that's why they're the media empire billionaires.