And that's just the people who have submitted early. With more than 14 hours left, that number will likely be well north of 1000 (though probably not many are using Dart like Notch).
Ludum Dare #27 had about 2200 games, from both the Compo and the Jam.
There'll be more like 10,000 doing it at near the end of January (possibly me if my girlfriend manages to drag me in this year).