From Diablo Wiki
Cheating in a game can mean two things; either built-in cheats, like unlimited life, or gold through some secret password or key pressing combination, or malicious hacks to the game code by third parties, or use of exploits.
Diablo I and Diablo II are plagued by hacks, and Diablo I even had a very common "dupe" exploit that many used in the earlier versions of the game, that Blizzard had problems to patch away. Many players are worried that Diablo III will be equally plagued by cheats and hacks. The difference is that Blizzard have learnt a lot from making WarCraft III and World of WarCraft, in terms of stopping hacks. There certainly ARE some hacks in 'WoW', but they are easily recognized by Blizzard, and the hacker will get banned permanently. The new account system in Battle.net 2.0 will also help making people accountable for their actions. Two strong reasons for an almost hack-less environment in Diablo III are:
- Blizzard has a whole team made up to stop hackers and exploits. They have become significantly better at what they do as they have gotten experience through other Blizzard games.
- Even if some new hacks can't be stopped initially (or perhaps ever), the Warden as well as the WoW client will know that a hack was made, and that copy of the game will then never again be surfing Battle.net, as soon as measures have been taken.
- The way we handle cheating is almost the same across all our games. Battle.net is the same group for all of us except WoW - but they have representation there as well. Can I give specific examples? Not really, because it's kind of technical and I'm not very technical. But the same group that work on Diablo 2 worked on WoW; worked on StarCraft; worked on StarCraft 2 - Security is their obsession. I would hazard to say we have the most security conscious and experienced staff in the world at solving this problem and that's what they will focus on. It's one of the reasons why the online group is a common support group for all us - we all benefit from the experience of all the previous games.