People just stopped using xfire ( seems like you aswell LP ). Getting the Xfire ingame function to work would get them back. Ffs you can go to other instant messengers through xfire even, so you could chat to your MSN people while you are still fullscreened on DR.
Though I will never stop using it, it just has too many valuable functions
Anyway I guess you could say there are about 100 ppl playing ACTIVELY ( not character but person wise ), but that could also be far from the truth. A GM would be able to give a more precise average though.