The Quake 4 demo released last night was apparently issued prematurely, and the following note describes the situation and plans for a follow-up:

Here's the deal, the QUAKE 4 demo that is on a few sites is an untested version of the demo that was inadvertently on id's FTP. The FTP has since been updated, but not before this incomplete version got out. The multiplayer portion of the demo doesn't work online at the moment. This version is not tested and not final, so if you can let folks know that they should wait for the final version that we're expecting early next week it would help.