It is worth noting that when something goes viral we still don't know why. Facebook represents the ultimate in viral success. Given we do not understand why things go viral then it stands to reason that the underlying software methodology is not causation. This means that the fickle finger of fate could easily be visited upon Facebook the same as with MySpace and Facebook will be in no control. This is independent of the any software methodology they use.

Claims made without evidence can be dismissed without evidence.