Yes, it can be withdrawn for real world use. However, Blizzard has stated that you have to decide at the sale/bid point whether the money will be either cashed out right away or used in game. Once that choice is made, you can no longer change it. They mention that indeed they are no bank where you can store cash for later real world use, so you have to decide before you actually get the money what it will be used for.

Cash deposited in your battle.net account can not be cashed out at a later date.

If you read the whole thing they go into detail. You do need to use a 3-party organization, but I think (from what I read) they meant that something like pay-pal would connect to blizzard and your money would be in a pay-pal account and then you could get cash. Of course, there would be small processing cuts at each stage, encouraging you to remain in the bnet store.

From the Diablo 3 AH FAQ

Q: Can players choose to get cash from currency-based auction house sales, instead of having the proceeds deposited into their Battle.net account?

A: Yes, as an advanced feature, players will have the option of attaching an account with an approved third-party payment service to their Battle.net account. Once this has been completed, proceeds from the sale of items in the currency-based auction house can be deposited into their third-party payment service account. “Cashing out” would then be handled through the third-party payment service. Note that this process will be subject to applicable fees charged by Blizzard and the third-party payment service. Also, any proceeds from the sale of items in the currency-based auction house that have been deposited into the Battle.net account will not be transferrable to the third-party payment service account. Not all regions will support this advanced feature at launch. Region-specific details, as well as details regarding which third-party payment services will be supported and the fee that Blizzard will charge for the cash-out process, will all be provided at a later date.

Blizzard says they are in talks with some online banking companies (PayPal, probably) to allow you to withdrawal the money.

That wasn't really the point of the comment. So you can sell something for real money and have it deposited? Suddenly, such things as money laundering laws could easily be an issue.

Matt touched on this sort of issue with the following paragraph:

"There are strict auction rules out there that vary from state to state, as well as income reporting and other rudimentary documentation that has to go on. Is my Diablo 3 income taxed? If I sell enough Stones of Jordan, will I be bumped up to another tax bracket? Suffice to say, there are many implications that a Diablo 3 cash auction house could potentially bring, but as an evolution of the way players interact with their virtual goods, it's a milestone."

So, would my transactions be tracked to try to prevent money laundering? Suddenly, with transactions being tracked by the Feds, what's to stop the IRS from coming pounding at my door about me forgetting to file income over it? There's a lot of things that can make this into a horrible development, initially at least.

Then again, it might put things into perspective with items. If this were to be implemented in WOW, would being able to sell a BOE for a hundred bucks make a big difference in how you'd view it? I've never done so, and don't really have any plans on doing so, but for the purposes of writing this, I checked the prices on some of the black market sites for selling BOEs. The normal 378 BOEs are going for about $130. So, as at those prices, the BOEs must be selling enough to pay for the bandwidth of the site and a wage of some sorts for those who farm such things. So, if I get together with 10/25 of my friends, and go farm a few of the easier bosses in Firelands, it wouldn't be unreasonable to be walking away with a few hundred bucks worth of BOEs. There are so many implications of that sort of things.

@Talmar. Holy hell... I should have kept reading before making my comment above.

This is absolutely going to create a cottage industry of people playing Diablo for a job, and not just Chinese prisoner slaves, but real Americans and Canadians sitting down and making money. And think about guys like Fox and Basil, who are WoW Millionaires - using their AH business to sell gold on the real money AH - might we see the first gamer millionaire in this system?

As a semi-pro AH'er myself, I have to say I'm very intrigued at the thought of a career change. This is an unbelievably massive gamechanger, I think this is going to affect things way more than anyone expects.

If you think about doing this for "real money", consider that you still have to compete with the chinese gold/item farmers who are willing to work for 12 hours plus per day for almost nothing. Considering that currently, if you were so inclined, you could buy 10K gold for $20 or so, and as the price would likely drop with a legitimate in-game transfer mechanism (no need for external websites/payment solutions/hassle-free transfer) how could that realistically be "worth your while" if you live in the US?

This reminds me of a Wired article where this geological analyst or somesuch figured out how to dramatically improve his odds with scratch tickets (this was mostly a design flaw in certain [but numerous] states and provinces).

In the end he decided to not take advantage of his knowledge...but only because he made far more money at his current job. He figured out that, even with the stars aligned, and his processes absolutely min/maxed, he'd earn $45,000/year tops. With the amount of open competition that will likely take place in Diablo III's AH, I'm highly doubting players will see numbers even *remotely* close to that.