ID Software updated their website about the recent release of the Quake 4 demo. Apparently it was a bad build of the demo and the official one has not been released yet.

"We tried to get the word out to mirrors and websites that multiplayer was broken in the build and not to mirror the file, but due to the late hour and the impending holiday, the request to pull it back was too little, too late."

Read the post over at the ID Software website.