Strange bug, this one.
I get this grey box when attempting to load the InFamous: Second Son trailer using Google Chrome Version 24.0.1312.57 m in standard mode. It happens directly after a top bar pops up saying "Resuming video from saved location". This happens regardless of whether or not I'm logged in.
I've cleared all my cookies and cache and the problem persists, but only with this specific video; other videos seem to be fully functional.
Further adding to the strangeness, when this same video is opened in Chrome using Incognito Mode, at the same time and regardless of whether or not I'm logged in there, it works correctly.
The corner case of all corner cases but I wanted it up here in case someone else experiences it more frequently.