Priivate servers are ilegal, i would suggest keeping away from them.
Technically, private servers are illegal for World of Warcraft. Nevertheless, many people still play on private servers.
No, only on private servers
Private servers are... well... private. It depends on what the administrator of the server allows.
of cource they are...well 99% of them
There are no GM power hacks on retail (legal) servers. There might be on private servers, but private servers are illegal. We can not help you with that here.
When World of Warcraft: Cataclysm hits the shelves and goes live on the servers, it will be the LATEST expansion. There are more planned, however Blizzard has not released any information about those expansion as of yet. It will be sometime before the next one is ready.
Unfortunately, yes there are people who run private servers for world of warcraft. Keep in mind that these servers could be several patches behind the live official servers, and the Game-Masters of these servers follow no rules unlike the official servers. The economy of the private servers is nearly non-existent because of the amount of people on them compared to the official servers.
Private servers are known to be buggy as heck. It is better to just play on the live official servers.
Sadly, yes, BUT only if you play on official servers. If you do your research and homework you can find private servers. Bad thing is that private servers are buggy and dont have that many players on it.
This is the problem with private World of Warcraft servers. They are full of bugs. You should go play on the live official servers. Much better.
Private servers are not supported by Blizzard and playing on one constitutes a breach of the Terms of Service you agreed to when installing WoW. If you are found out, you will be banned and your game will be unplayable with normal servers.
Because of the new expansion, World of Warcraft: Wrath of The Lich King, no private servers of any merit are able to emulate the game properly... it will be months before any private server will be able to create a bug free emu.