A post on BASHandSlash describes how to force Call of Duty: Modern Warfare 2 to select you as the host for multiplayer games. This quite plainly highlights the obvious problem with the lack of dedicated servers, and though this is not going to be news to most of the folks reading this, it bears repeating if it can help future games avoid the peer-to-peer multiplayer mistake going forward:

Hosting the game on your computer puts you at a very great advantage. You will have the lowest effective ping in the game (approximately ~20ms). It's the host's computer that decides the outcome of every battle, which means that what the host is seeing on his screen is the closest to what the registration algorithm thinks is actually happening.

A week ago I tried an experiment with Whiskey, a renowned CoD gamer from British Columbia. We set up a private match and we played a 1v1 death-match on Rust.

When I hosted (I'm in Toronto) I completely pwned. I had a K/D ratio of three. Yet...when Whiskey tried to host, the tables turned. The host was getting that split second that separates fragger and fragee in FPS. When I was hosting I'd see the enemy's head suddenly pokeout around the corner just long enough for me to blast away, whereas my opponent would see nothing.