In short, there will be 2 separate Auction Houses, one that utilizes in-game gold, and one that utilized real-life currency, and players will be able to choose which Auction House they wish to use per individual transaction - in other words you won't have to choose between the two.
The way I imagine it working, will be if you want quick, easy sales - use the in-game gold auction house. If you have a very very rare, high-ticket item that you don't mind being patient with, use the real-life money auction house. Of course there is no reason why you wouldn't put either of those category items on either of the auction houses, it just seems less likely right now.
First thing NOTE: this information was posted on MMO-Champion, WITHOUT any source links. They state "Originally Posted by Blizzard Entertainment" but usually the words "Blizzard Entertainment is a hyperlink, this time it isn't - so take everything here with a grain of salt.
Sinuviel brought up a good question in one of the World of Warcraft related IRC channels:
Originally Posted by Sinuvial
Who is going to be able to check if it is Blizzard, or a player selling goods anyways? Blizzard Trader-X makes an account, uses some l33t getItem command and posts some pure profit items on the AH. Nobody can tell if he is an actual player, or a Blizzard employee!
Something else that I want to point out is Auction House cuts and Deposit Fees.
25 million players.
On average, each player sells 5 auctions per day.
Blizzard puts a 1 cent AH cut per auction.
25 million cents per day.
It's clear that, if this is true, Blizzard is finally facing the facts that Gold selling/buying is an unstoppable force. I just wonder what kind of exact effect this will have on the game's economy. Ever since pre-bc, players have been constantly bringing up the suggestion that Blizzard should allow buying and selling of gold with real-life currency straight from their website.
I'm not going to spam you guys with all the FAQ quotes by Blizzard, but I will post some of the more interesting ones that are more relevant to our community. When Blizzard releases more information and we get proper source quotes I'm sure one of the news team members will do an update post on the situation.
The fact that Blizzard themselves will be selling gold for real life money will be an absolute killer to the gold buying and selling private industry, but I'm sure there will be a few who try and undercut Blizzard or even dupe players into thinking that they are Blizzard.
What about bots? I'm sure we will see an absolutely insane boom in the amount of bots running around the show, trying to scrape up as many shiny items as possible to trade for real cash.