Facebook will be alive and kicking until Google+ has Farmville.

On a different but related note, say there's two gas stations on your way home. (Yes, only two.) Once the system is hacked, one station could feed false reports into the stream saying that traffic is gnarled around their competitor... people might be more likely go to the one that isn't as traffic-licious. Or, to extend this, what's to say that Shell wouldn't do this to all Exxon station, for example?