I never understood why people ask GMs questions like these - GMs are the lowest paid employees at Blizzard and do not set policy. They are the "tech support" of WoW, the people with minimal training who basically have an internal knowledge base they use to answer questions, and are not allowed to "make up answers". They don't get to decide if multiboxing is ok, or if Keyclone is cool, or how RAF works. Blizzard devs decide that stuff, and it can change anytime Blizzard management wants it to.

For now Blizzard thinks multiboxing is ok, it brings them in more income and doesn't really hurt other players. if Blizzard ever released an MMO that was free to play (advertiser supported, etc) then you can bet your sweet ass that multiboxing would not be allowed.