Why Halo Reach will outsell Halo 3

[Seece]

SecondWar said:

Seece said:

Call of Duty 4 was a fantastic game, didn't have a huge first week, but had massive legs. But most importantly, it had loyal fans/players, this in term with the massive marketing MW2 recieved, is why it did massive first week numbers and has already outsold MW1.

This bits confusing me, how can Call of Duty 4 outsell Modern Warfare 1? They're the same game?

Sorry I didn't word that correctly.