We don't need no stinkin membership. Audiogon needs to just charge a tiered one time up front fee for ads. This way there will be no conflict of interest if people communicate outside of Audiogon. It's easy. It's simple and it would discourage fraud big time.
Premium membership
Would you pay for a premium membership or gold membership type subscription here ?? This type of system where selling items to these type membership only persons would be available as well as other services. This I think would keep the non payers who commit to making a purchase from being a nuisance to members selling. These defunct payment type of people would most likely not buy into a membership, and if they wanted to buy an item from a paying membership person that they would have to pay a non refundable fee to Audiogon to buy something from a paying member trying to sell an item.