It has been revealed in a recent interview with Robert Bowling, the Community Manager from Infinity Ward that Modern Warefare 2 will feature a new system called IW.net. IW.net will do away with having dedicated servers or indeed 3rd party style mods for the game, without them first being approved and then incorporated into IW.net. One of the claimed reasons for the change over to IW.net was Piracy however its not the whole reason.
To further kick the dirt into your eyes Punkbuster will no longer be the recognised anti-cheat system and instead is being replaced by VAC. This of course means that for PC users Steam will no doubt be a compulsory install.
As you can imagine all this has caused a huge uproar from the community behind Call of Duty, and rightfully so as these changes will do away with privately owned clan servers (only option will be private matches via IW.net), professional mod’s for clan matches and custom maps.