Blizzard has announced that a "silence penalty" will be given to players who are abusive or partake in inappropriate "chat behaviours" in World of Warcraft.
This will silence the players in question and once the ban is in effect those who are reported for Spam or Abusive Chat categories will be investigated. Guilty verdicts will result in an account-wide penalty that will restrict options for chat.
Silenced players will not be able to talk in chat or global channels that are auto joined, nor will they be able to send in-game mail either. They will, however, be able to do things like create parties and raids as well as whisper to friends.
This penalty will come in a patch prior to the release of the Legion expansion which is set for release on August 30 and will hopefully act as a deterrent for potential offenders.