Blizzard announced at the end of last week that UI modders can continue their fine work, just not make any money off of it. Likely in response to recent Adware add-ons, community response has been a mix of understanding and outrage. This could very well set the pace for the future of MMO game add ons and place the responsibility squarely back on the development companies shoulders. A sad day for the modding community but a happy day for Blizzard who can shut down some craptastic adbased software.

Source: WoW Official Forums