Considering that the smallest object that Hubble can resolve is about 100 yards, that would be a pretty mean trick. Even with robotics doing the work, it would take decades. Just to be visible to the unaided eye... and you'd have to be looking for it... it would have to cover about 3% of the lunar disk... about 200 miles square (40,000 square miles!) To advertise FB on the surface? That would be a big *****' "f"