WoW World of Warcraft Private Servers
You can find an up to date list of WoW Private Servers at GS200.
For those who did not get selected as a beta tester there’s a long wait before they will be able to play the game. For some this wait would be too long so they decided to use their programming knowledge to create alternate/private servers for World of Warcraft that anyone could play on. These servers do not have many of the features that the official servers have and they’re often unstable and full of bugs. The where and how of these private servers can be found at Skryer.
The reason these private servers are so limited is because the creators of the servers has to program all the game mechanics themselves; almost everything that happens in a MMORPG origins from the server itself, therefore the information from the official World of Warcraft source code cannot be reached. Blizzard does not support these private servers and it is considered morally wrong to play on these servers.
Note: The official developers, in this case Blizzard, frown heavily upon such servers and do not support them in any manner