If I may add a little to this, what I know, what I speculate and some of what I wish...
Global Auction House
Brad talked about having a vision for a "Silk Road" type economy, where items on one side of the world were valued and needed on the other side of the world, encouraging players to farm at one place (Fox Tails in Wild End for example) and transport them to the other side of the world (Thronefast, Fox Tails available but at about 1/2 the rate they are in WE) there are other items as well, Ash Logs needed for quest, Easy to find and get to in Thronefest, very dangerous to get to in Wild End (at least I haven't found a safe spot to farm them) This Silk Road concept would be nullified by a Global Auction House. I believe ruling the Global possibility out.
Auction House
There have been amazing discussions on the web site over the years about how they should do Auction Houses, from a surprising (to me) number of people wanting nothing more than what we have now, the East Commons Shout it in a /auction channel then get together face to face (this IS intended to be a social game) method, to an in town Bulletin Board, to a full-blown WoW Global Auction House, I don't recall the Dev's ever contributing much if any of their thoughts, just that they were watching, and reading.
Bulletin Board
Not to say this is what they Will or Will-not be doing but step out of the bank in Avelia and look to your Left... right there against the East wall of the Inn is what appears to me to be a Bulletin board. You now know as much as I do about that, but I consider that very suspicious, maybe Jothany can clarify this before vicious rumors get started about it?
Craigslist Classifieds
I hope they take player selling to a new level, a daily/weekly published Newspaper for each city/settlement. Players can place an ad in this newspaper for more than just Fox Tails, Cotton or Ash Logs, they can post services, events, guild recruiting. These Ad's don't need to be attached to a Board in town they can be a book in your inventory. You can take this with you out in the field while grouped or waiting for a group, waiting for a boat, Brouse/search it while your medding, group members AFK, ect... filler for all these "I don't have time to sit there and do nothing" times. This wouldn't impose on Brads Vision for Silk Road, it may or may not transfer the item, I would prefer NOT but it instead would assist you in getting in contact with the seller, a /whisper button or a Mail-to button so you can set a time/place to make the sale, this wouldn't impose on the Pro-East Commons Shout and sell face to face social crowd. IF the Devs decided to peruse this option, I'm sure they can make it so much better than I laid out here.
but then there is that board in Avelia......
That board may be something to watch later on, I never paid it much attention gee thanks now I will keep an eye on it :P I think the /auction is ok but if no one is around and someone wants to sell/buy something at an odd play time a sort of auction house or Auction board would be the way to go
@Raiban
I know the buy-it-now auction house method or even the transfer it by mail method is more convenient, but this steps on the toes of the /auction crowd that's main goal was the face-to-face social interaction.
Thats where The Availia Tribune (Newspaper Classifieds) comes into play, each ad could have a "Whisper" button if the seller is online that would switch to a "Mail" button if they are offline (once a mail system is online) and maybe a /who *Seller* information to know where they are, heck, they may be right next to you or in the same town, maybe buyer's in Demith and the seller's in Availia and you can make a plan to meet at zone line. Maybe that Fox Tail is 50 coppers if you buy it here in Demith (connivant) and the seller's not online, but somebody has them for 5 coppers in Soriryth or 30 coppers if you buy a stack of 10 (bring them back and make a profit) and he will be online for an hour... can you find a port?
Edit: to elaborate a little more, the Newspapers could be a commodity in themselves. The Availia Tribune, The Demith Gazette, The Kingswatch Dispatch, The Skydurbin Observer... 10 coppers from merchants (use for the Town Cryer maybe?) in their respective towns, Players could buy a stack and sell to players for more in other towns.