This is a pretty good read: 5 Anti-Piracy Strategies That Screwed Over Regular Gamers, some of the early measures are pretty extreme. I remember number 1 happening quite well!
well the only way of preventing a piracy is making a completely online game and making it free to play but in game purchase items man when i was kid there were so many quality single player games. i don't know if any comes out recently
Even on-line only games can be pirated, i know people have made private servers for World of Warcraft. Not sure how good the experience would be though.
The experience isn't good, it's the same as with the emulated diablo 3 server, it's buggy, drop rates are toootaly unexpected and worst of all, sometimes you wonder into an empty are, just because. The server reverse engineering takes a crapload of time thus the quality of early releases is "lacking", and a minor update can flip the table even on the already stable versions of emulators.