They absolutely would. As I said above, "the NSA is supplementing its email-and-phone metadata database with... Facebook profiles."

The point I was making (perhaps poorly) is that the NSA is surely bulk vacuuming up public Facebook profiles and using its relationship with AT&T/VZ/Sprint/etc. to do fiber taps of poorly encrypted or unencrypted data in transit. But there's no evidence of direct access to Facebook/Twitter/G+ servers or bulk downloads of private data from social networks.