Dallas - Sep 20, 2006 - Bid4spots, an online auction for unsold radio ad inventory, has reached the $2 million milemarker on its first anniversary. The company has awarded that amount of auction winnings among its participating radio stations. Participants in the online auction bid ad rates down and the lowest bidder wins. Nearly 2,300 radio stations in the United States have participated in the auctions. Launched in September 2005, about 900 advertisers and and 180 ad agencies have enrolled in the Bid4spots.com system to buy last-minute airtime from radio stations.