We did consider building decentralized markets, and some form of Smart Contracts protocol into the actual coin using multi-sig and Bitmessage and we may still go this direction after we are happy with the site.
If anyone is looking for a flag, this is a good one.
The old decentralized market trick

Note, we're not a decentralized market place.
It was an idea which we felt would have been more of a technical exercise and not really used.
There are plenty of coins with decentralized markets, and basically nobody uses them at all.