Chris Butcher(Engineering Lead, Bungie Studios) will be speaking at a GDC 2008, Game Design Track and Programming session titled "E Pluribus Unum: Matchmaking in HALO 3". The session placed players in a matchmaking game and described the algorithms behind P2P matchmaking models and its implementation in Xbox Live. According to Chris Butcher there are 1.2 million unique users on Halo 3 online every week and retains almost 80% of their online players. 84% of the games played online are ranked matchmaking with Team Slayer being the most popular matchmaking type.IGN: GDC 2008: People Like Halo 3 (February 20, 2008)