This evening Google is expected to unveil an ad-planning tool, targeted to media buyers and agencies, reports The New York Times.

Today marks the start of the Advertising Research Foundation's New York media conference. A Google presentation is scheduled for 5pm.

An anonymous person said the tool, dubbed AdPlanner, uses search engine data and third-party information to determine what demographics a site attracts — a function that will enable agencies to pinpoint which sites actually serve their target audience, regardless of what the media kits claim.

Upon debut, AdPlanner will be available at no cost.

This week Google launched Trends for Websites, which enables users to compare traffic data between websites.

On a panel at Cannes, Google exec Henrique de Castro assured audiences that the search engine giant aspires to "stimulate [online advertising], not short circuit" agencies.

"The best results are when we work together with agencies. We are not going to replace people [in the] advertising world," he added.

"We don't have the strategic relationship [with clients]. We don't have the capability, we don't want to be there."