That tells you which retainer and where is selling the item that you're searching for, if any. It should not show prices in order to keep it competitive, but should allow you to search for specific items, or at least list all items that are being sold in the zone. E for "buy" could be replaced on that board with E for "put a marker on your map". I think that that would greatly improve the quality of life of both sellers and buyers - if your guild's trading post is put somewhere in a small village rather than a main city, however other people had an ability to KNOW that you're selling something that they want, they're more likely to visit you and buy from you, while from a perspective of a buyer, they don't need to teleport all over the zone, they only need to teleport to the board location, find out where the items that they want are (or if they don't exist in the zone) and then teleport directly to the traders.
What do you guys think?