The Diablo III Forums have word that Blizzard has been quelling a rise of the machines in their action/RPG sequel, announcing several thousand players have been banned for botting. In response to a criticism that this action is belated, a later post notes that they have been taking such actions all along, but are planning on being more communicative about the process. Here's word:

We've recently issued account bans to several thousand Diablo III players who were found to be using botting programs while playing. In addition to undermining the spirit of fair play, botting, hacking, and other forms of cheating can also cause technical problems with the game as well as contribute to performance issues with the Battle.net service. To learn more about our exploitation policy for Diablo III and how it may affect your gameplay, please visit our official support site.

As always, maintaining a stable, safe, and enjoyable online environment for legitimate players is very important to us, and we'll be continuing to keep watch on Battle.net and take action as needed. In the meantime, if you wish to report the possible use of botting programs to Blizzard, please see this thread for more information. (We will also be adding the ability for players to report this kind of behavior directly through the game client in a future patch.)

For questions regarding account actions, please refer to Account Administration.