A system for buying and selling click-through traffic from a seller's web site employs an intermediary web site for conducting a multi-buyer pre-bidding trial of click through traffic so that a plurality of interested buyers can see for themselves what level and quality of traffic is generated to their webs sites. The trial is conducted with each buyer in turn during a trial period prior to opening bidding by the interested buyers for click through traffic from the seller's web site. The trial is conducted by placing a trial link on the seller's web site to the intermediary web site which links to each buyer's web site in turn during the trial period. The intermediary web site measures the click-through traffic during the trial process, so that the participating buyers are informed in real time of the actual performance of click-through traffic.