You can already download all of the extra content from the Game of the Year edition for free. Packaging it onto a CD allows people who haven't bought the game yet to get (1) the most up-to-date version of the game without downloading patches and (2) a bunch of stuff on one CD without going around the web to find it.
The most important content that will appear on the GotY edition that you can already get for free is the Game of the Year map pack -- 4 new multiplayer maps (6 on the CD if you didn't grab Ice and Tram already) from Nerve and Splash Damage. Some other stuff in there includes the Making Of RtCW movie "Behind Enemy Lines" (about a 13 minute movie with interviews with all the dev teams, etc.), game demos, all the desktop wallpapers that we released, and some more stuff.
So if someone didn't buy the game and they want all that stuff but don't want to go scouring the net for it, it's all right there. If you don't want to get the GotY edition, however, you can still get all that stuff for free.
This comment was edited on Jun 18, 13:50.