The ad world is rife with companies fighting to act as middleman between advertiser and media, and the competition is fierce. This week alone, three huge players made news.

Google (NASDAQ:GOOG) announced its version of an advertising auction house, in partnership with satellite giant Echostar (NASDAQ:DISH). The search engine company is offering to act as middleman for ad purchases on the Dish Network, as well as delivering the product and provided detailed metrics measuring its impact. The screaming you hear running through the cable industry is because this threatens to encourage other advertisers to demand the same info from cable providers, information they have been very cagy about divulging. Imagine what would happen to their ad rates should Procter & Gamble (NYSE:PG) discover that 75% of all viewers switched to another channel during their commercial breaks.

DoubleClick, rumored as a takeover target of both Google and Microsoft Corp. (NASDAQ:MSFT), announced that it is setting up an auction-like exchange to match buyers and sellers of digital ads. The service will allow advertisers to see what others are paying for their placements. DoubleClick already acts as a service bureau for those wishing to place internet advertising, as well as providing metrics to gauge its effectiveness. The company, owned by private equity firm Hellman & Friedman, is worth an estimated $2 billion, and success in this expansion could boost its value dramatically.

On the down side, eBay Inc.'s (NASDAQ:EBAY) nascent experiment in electronic ad auctions hit a major roadblock when the Cabletelevision Advertising Bureau (CAB) declined to participate in the trial. CAB initially was an enthusiastic participant in the venture, but apparent reluctance by media sellers who feared being cut out of the market caused the Bureau to reconsider its support. Supporters of the pilot program include Microsoft, Home Depot (NYSE:HD) and Intel Corp (NASDAQ:INTC). eBay has put the program on hold while they regroup.