The auctions are great and all, but I would really like to buy a store and own it. I don't know how this would fit in with Glitch, but love my store in another game I play (Kingdom of Loathing).
I have seen other people talk about the desire to own a store. The way I see it there are two options for this: in-game like a house or out-game (is that even a word?) like the auctions.
I like the idea of in-game accessible stores, but not per se physically present in-game like a house. They could be accessible from a few streets in Ur, maybe one per region. You could make all the shops accessible from every region or go for a more local approach with separate shopping area's. Just like the auctions you would be able to search all shops at once (of per area) to hunt for a bargain. But you would also be able to search for the store of a specific player.
The shopping area would be like a portal to the different stores, once you decide what you want to buy from which Glitch you would have to "travel" to the store to make the actual purchase. Maybe a cardboard version of the owner would greet you :)
Pros: no more listing fees and commission, easy to make price adjustments, in-game trading experience
Cons: like a house you would have to pay for owning a store