By shard what I mean is somethign akin to a "logical" server. Basically the world that the players play in. For instance, World of Warcraft has well over 100 shards (which people sometimes also call servers, hence the confusion), whereas Eve Online is a single shard. In Eve Online all the players of the game play in the same virtual world. Each shard is often made up of seperate nodes, which are then made up of several physical servers.