We have now implemented a system similar to what eBay has that allows you to rate buyers and sellers. A users rating will only be shown in the spam sections and can be found under their avatar below the post count. I am still working on the style of this a little bit, the number is a little small and I think it is not obvious enough that it is a clickable number. When you do click it you will be taken to the users buyer/seller page. Here is mine http://www.performanceboats.com/itrader.php?u=1.
I plan on expanding the capabilities of the spam section over the next couple weeks, this is just step one in the process. As the spam section expands I belive it will be very useful to know who is really good to do business with. We will be tweaking the settings a bit for the next few days, but for the most part the system you see is what we plan to go with.
Abuse of this system will result in a loss of privileges. Extreme abuse will result in a ban or other infraction.