I have managed to find a few articles and podcasts with interviews in relation to this topic. Many of them very dated. Much more so, I am finding lots of rumors and speculation.
Here are a few things that seem to be certain.
1. There will be no mega auction house for the entire server. (ie GW2)
2. There will be Guild Stores. (Same thing as an auction house)
3. Guild Stores will be located in Cyrodiiil Keeps that are controlled by said guilds.
4. You must be a member of a guild in order to post items on the Guild Store.
5. Anyone within the same faction may browse/purchase items from Guild Stores.
6. You may be a member of up to 5 guilds.
If I am missing anything important or if any of that is incorrect, then please feel free to correct me.
Here are a few concerns/questions I have that hopefully someone can shed some light on.
1. Is there any way to post items on a guild store if you are not in that guild? At the cost of a proccessing fee perhaps?
2. Are the Guild Stores only found in Cyrodiil? If so, what happens to all the posted items if said guild loses control of the keep?
3. Will there be any other form of open market like an established location where people can go to buy/browse/sell wares?
4. Will there be a trade channel?
This system has potential, but I have to admit that I am skeptical. A huge part of the MMO experience for many of us is the open market and buying, selling, trading with other people.
Please feel free to comment, add to/delete from anything I have posted here. The idea is for all of us to get a better understanding of how open trade in TESO is going to work in order for us to be prepared.