UPDATE: It's back up, no official word yet.
Thursday March 25, 2010. Story of the day - Youtube is down. For as long as an hour now, Youtube.com is showing this message: "Http/1.1 Service Unavailable" or "500 Internal Server Error".
So far we have no official word from Google on this downtime. In the meantime, users from all over the globe are pouring their anger, flooding their Twitter posts and Facebook wall.
Let's keep an eye on this unusual downtime of a Google service; we'll update you as more develops.