I believe it would be helpful to have a place to go to for research before you deal with a particular vendor. However I would recommend including not only problems but also good business practices. I don't mean a 6 paragraph love letter, just a few comments about knowledge, price, shipping, returns, accuracy of information and general helpfulness. With information, both good and bad, you can make a decision on whether you want to do business with the vendor. This should, as Chris suggested, be ONLY first hand information. I don't have much time for things such as, "I heard "or "someone told me". It shouldn't take long to figure out who is customer friendly and who is not.