Couldn't care less. The CoD franchise spiraled downwards after the United Offensive addon. CoD4 was one of the most overrated games of all times to me, using the same, shallow formula of all the other parts, just with different models: You go to an area,many enemies spawn at only a few different locations (like 10 times in the very same window of a building, or exiting the very same entrance).
There are so many better games, like Red Orchestra, if you like WW2 (warning, Multiplayer only), or the GRAW series (which itself is a step down from the great original GR though) or Armed Assault...