Ars Technica - Modern Warfare 2: the case for the dedicated server.
The lack of dedicated servers also means Activision Blizzard controls what mods, if any, will be allowed. You can't control what maps are running on the server, and fan-made maps offered for free may be a thing of the past, replaced by for-pay content, if this model catches on. This changes the relationship between the community and the publisher: you used to be able to buy a house and move in, but now you'll have to ask permission to paint the walls of your rental. Which, by the way, is more expensive. To show you just how far Infinity Ward has come since the last Call of Duty in terms of embracing the PC platform, take a look at an interview shot for the first Modern Warfare.

In just a few short years, we've gone from embracing the mod-making and PC gaming community, to treating them like children who can't be trusted with nice things.