Millions.
Two players on one screen. Ten players online.
cap of 9 vs 9 on multiplayer online
Special-Ops (2 players max) and Multiplayer (Up to 18 players in a single lobby)
Call of Duty: Modern Warfare 3 for Wii in only single player.
Sixteen people tops per certain maps if you play online. Through one local system, four.
25 million people and still counting :)
Yes, there are many invisible, godmode, aimbot, etc players found on Modern Warfare 2. Some even have the ability to infect other players, in turn giving them the mods as well.
activison has not confirmed it yet but many players suspect it as modern warfare 3 is not summed up fully yet
Yes there are many different mods and is commonly done by players.
13
2.3 million people still play modern warfare
None. the first ones are in Modern Warfare 2.