Nope you guys are crazy if you think Mw3 is ahead LOL
Mw3 has like 150k on online playlist and 290/300k Total.
Halo 4 alone on MP has over 350K and most of the people is playing campaign anyway.
Gears of War 3 was the same 120k people on Multi and 320k people on campaign on Arcade when i got the game firt day.
So Halo 4 probably already had 1-1.3m concurrent users, thats alot but Next Week Black Ops 2 is gonna make that number look like a joke.