private servers started in Van WOW, within months or less of launch.
for years prior to 2004, many gamers used hacked games, no CD hack codes, bit torrent downloads to avoid paying the box price. back then i had on my PC... GTA (SA, vice city, liberty city, CODUO, WC3 later WC3FT, legends of aria, Quake, Doom, unreal gold, lord of the rings (like WC3 in play), far cry, various F2Ps, and many more, all for free. when it came to WOW alot of gamers did not want to pay a box price and a monthly sub, that was the main reason for the start of private servers.
WOW was one of the first game that locked the game down, making it hard to dupe, move items player to player, due to files being mostly on their servers. GTA series after SA, starting locking their game down with registration, CD check, email, etc verification system