Recently, Blizzard has issued "several rounds of account bans for cheating" within Diablo 3. These crazy kids were found to be using hack programs to exploit the game. Some of these hacks even allowed players to zoom the game out to ranges beyond normal gameplay and attack enemies before their AI could trigger. How rude of them.

(via Battle.net)
As a reminder, we don't permit the use of hacks or other third-party software in conjunction with Diablo III. Most of the programs out there that are intended for use with the game are actually cheat programs and automation programs ("bots") that exploit Diablo III's mechanics and provide players with an unfair advantage. However, "third-party software" also refers to any file or program that attempts to:
- Obtain information about Diablo III that's not normally available to the player
- Transmit or modify the Diablo III game files
- Provide access to features or abilities beyond what is allowed by the game's design
- Change how Diablo III interacts with Battle.net

(via Battle.net)