We will continue to aggressively monitor all World of Warcraft realms in order to protect the service and its players from the harmful effects of cheating. Please note that selling World of Warcraft content, such as gold, items, and characters, can result in a permanent ban of the involved accounts from World of Warcraft.
You could really feel it when it happened on EU realms, places like Azshara or Winterspring had at least 20-30 hunter bots grinding Furbolgs 24/7, after weekly maintenance there were none. There still aren't much herbs left to pick up unless you go farming during raiding prime time, but at least farmers you see are real humans. Those who buy such things reported gold prices also jumped up by 50-100% that week.