Lately, the devs of WoW have been making loads of posts over on the wide world of Twitter. One that really caught my attention was posted by Watcher today. Thanks to @StedeWoW for finding this out for us!
Now, what does this have to do with gold making you may ask?
You see, lots of people make gold by selling the Cataclysm levelling gear. It's the gear that people buy to get ahead into Cata questing and make it easier to quest.
Of course, once the patch goes live people won't need that gear. They can just get straight into the dungeons and such.
One of the other reasons for the gear was to get over the mininum ilevel required for the dungeons, which is also going away: (Thanks to @Mrpyrostorm for asking)