No dice on
that leaderboard, Jerry.

ContextWeb's ADSDAQ, an online exchange for site publishers and advertisers, has launched a "reach extension program" that enables publishers to fill campaign gaps on short notice.

"The program eliminates inventory holding cost for publishers and is essentially risk free since publishers buy on the exchange only when they have a specific need for additional audience and content," ADSDAQ wrote.

Publishers seeking added reach in a given category may submit a bid on ADSDAQ's Exchange. If inventory is available for the amount posted, they can buy it and roll it into an existing ad campaign.

The Exchange positions its model as "brand-safe" and comparable to site-specific or portal buys. It enjoyed a major jump in membership late last year. Competitors include AdECN, a Microsoft property. Like ADSDAQ, it invites comparison between itself and the stock exchange.