Halo multiplayer is dying. Microsoft and 343 would never admit it, but the data is right there. While their own internal metrics are likely much more comprehensive, a basic overview of the data was publicly compiled in a brilliant NeoGAF post. As you can see at the link, Halo 4’s multiplayer popularity came out of the gate strong, peaking at over 400,000 users, but lost nearly half of its userbase just two weeks later when Call of Duty: Black Ops 2 released.