“If youre a gamer who primarily plays single player games, you might be suffering from a constant sense of foreboding as new games get announced. It is the fear that this time it might be your beloved series or studio that is the victim. What exactly is this imminent doom coming to ruin everything you love? Im talking about online multiplayer games. In particular, the Massively Multiplayer Online Role Playing Game (MMORPG).”
Source: N4G PC MMORPGs for Single Player Gamers