Trading in the market is facilitated by the gribble bot, which takes care of maintaining the outstanding order book, as well as a web of trust user rating system. All trades are conducted between users directly, without any intermediation by the marketplace.
The source code for all the related software, including bot plugins and the website, is open, and hosted on this github repository.
The order book holds offers not just for buying and selling bitcoins but for physical goods and services as well.
Web of trust network
The OTC Rating System is an irc-based web of trust network. Users can give each other ratings between -10 and +10. User must be identified via a PGP key to enter ratings.
Only one rating can exist between two people. The 'rate' command updates the existing rating if it is used multiple times. So as the trust increases or decreases, user can update the trust value for a particular user.
Only users with positive ratings in the system can rate other users.
The system calculates the cumulative trust received by a user from all ratings. Through the web interface, users can explore the trust ratings and interconnections between users.
Users are suggested to take the size of transactions, the nature of your relationship and interaction, length of history, etc, into consideration with giving out rating.
The basic guidelines on what ratings to hand out to people.
|10||You trust this person as you trust yourself. Reserve this for close friends and associates you know in person.|
|8||Large number of high-value transactions, long period of association, very trustworthy.|
|5||You've had a number of good transactions with this person.|
|1||One or two good transactions with this person|
|-1||Person strikes you as a bit flaky. Unreasonable/unexpected delays in payment, etc.|
|-10||Person failed to hold up his end of the bargain, took payment and ran, fraudster.|
Relying on the rating
Users have several ways to check if the identity of the person is genuine. Once you check that the user is identified via PGP key, you can query his rating with the 'getrating' command (sum of all ratings) or the 'gettrust' command (total of ratings by people you trust). You can also explore the trust network and make sure that the person is well connected to a number of trusted users.