Blizzard is working on adding access to the AH outside of the WoW. The exact functionality isn't clear yet.
Currently I believe the WoW economy suffers from a lack of participation. When so many people only have a few hours and that time is dominated by raids or randoms or PvP; they can't afford to spend much time on the AH. This causes two problems: ignorance and impatience. If you have barely any time, you're not going to be seeing market trends, figuring out reasonable prices, perhaps even looking down the chain for crafting potentials. Post and get offline. The rush also means they cannot afford (or believe they cannot) to take risks with pricing because they don't have time or bag space to be reposting failed auction after failed auction as they learn the market.
Adding an extra 15 minutes, especially a 15 minutes in which they are not expected (or don't expect) to do dailies or farm or randoms, could be a big help. Those 15 minutes are for the AH only, so they are more likely to be spent learning and posting more thoughtfully. This means the typical player can get a bit more for their time farming.
This sort of external feed would also be helpful in developing an overall picture of the market. Imagine a few dozen people per server doing scans when they could, around the clock, and sending that data to a central listing. There could be a ticker of sorts for the AH. Currently this is possible, but would be quite tedious to do since the people would need to be online and not doing much for so long.
A bigger picture of the market would be a boon to anyone with that information. And there begin the problems. Who would control this information? The armory AH already sounds as if it will have a fee attached, so it's not inconceivable that websites would spring up to scan the AH and compile the information, for a fee. This could spawn a new age of real money giving significant in-game advantages. Things get blurry. The real money gives an advantage for getting in-game currency; is that indirect gold-buying? Will people feel pressured to subscribe just to keep up?
If the information is free and widely known, I believe it will help the common farmer or crafter. They will be able to more precisely charge for their goods and products.
On the other hand, if this does not become commonly used or known, then it may only give rise to a new speculator class, inflating prices and effectively siphoning away gold from the community, with no corresponding benefit.
This addition worries me with the potential implications: slippery slopes of real money advantages and extra charges just to keep up with the competition.