It's interesting how many people are mentioning the lack of online multiplayer. It always seemed to me that online multiplayer was never that popular on consoles until Xbox 360. The fact that you had to buy a $50 accessory (even on Xbox, despite having an ethernet port on the console already) didn't help. The only console with online capabilities standard was Dreamcast, which to me strongly implies that the poor internet support for the Gamecube was not much of a factor in its relative lack of success.