MMO Emulated ServersPrivate or Pirate?
Chris Maginnis writes:

"Back when MMO games began to grow in popularity, MMO gamers became jealous of a single player gamers ability to pirate their games. Free private server emulation was born. Today many of the latest games, including World of Warcraft, are available on free to play private servers. But are they legal? And what is the benefit of playing on a private server?

A private server is the common name for a server emulator. Essentially, a private server emulates the functions of a normal MMO server. It allows users to login and play as they would on a normal retail server. Private servers have gained their player base by being free to play and through content customisation. At the same time, they have been criticised for poor performance and low player population. There is mixed truth on both sides."