Bungie announced that they've reached their 5 millionth player to experience Halo 2 online. The number refers to unique Live accounts that have played the title. That doesn't mean people stuck with it or that each of those tags belonged to different people. Bungie reached the milestone on the 2.5 year anniversary of the game's launch. The real test of Halo's power will be this fall when we see how well Halo 3 moves Xbox 360 consoles.