All these developments make the future role of the advertising agency a lot murkier. Omnicom and Publicis are trying to take part in this technological revolution, operating “trading desks” that buy display ads for their clients on the new exchanges. But some big advertisers, such as Procter & Gamble, a consumer-goods maker, now operate their own trading desks. Media websites are increasingly, as Google does, selling their slots directly to advertising clients. Ultimately, predicts the head of advertising at a big American news firm that already sells a lot of its space through real-time bidding, “We are not going to need the agencies.”
