It has been two hours. Are all your clocks wrong? Or did guys get stuck in the shift in the space/time continuum?
Just kidding!
I think that's just a generic "two hour" sign they tack up when they are upgrading. (I've seen it before, when they've come back online before the two hours are up.) Otherwise, they get addicts like us, who'd be clicking the "Refresh" button every few minutes, checking to see if the site is back up.