Player A is the person selling gold.
Player B is the person buying gold.
A trades B an epic item (say valor point gear) and then has B post the item in the auction house for 20k gold. Player A then buys his own item back through the auction house and B receives the money he was buying. I believe a similar method was done using white items and generally worthless items, but perhaps with decent epic items it could appear as more legitimate? Comments?