Originally posted by longjohnsilver
Question 1
How to do this for all the perks isn't known. It is obviously usually related to the perk in a unique way. We do know a few of the challenges. For example
For marathon pro, you have to run 26 miles.
Ninja Pro unlock: Get 50 close range kills using ninja
Also for stopping power you just need to get a certain amount of kills with stopping power on
Question 2
Dedicated servers are mostly used on PC to host private matches that are highly customizable. Massive teams, custom maps, and other cool stuff. It also allows you to search for the game with the best connection for you. This wont be on MW2 for Ps3 (or PC now) but it has been put in before. Killzone 2 had a dedicated server system with customizable matches if you have ever played that