• by Joe Mandese  @mp_joemandese, June 27, 2011

Years after most of the major agency holding companies have launched or spun off branded audience-buying platforms, WPP's GroupM this morning said it was entering the game with a new company dubbed Xaxis. GroupM said Xaxis would combine all of the "demand-side data" and technology resources of WPP, and combine it with the "trading leverage" of GroupM's agencies into a "single comprehensive resource."

It was not clear how Xaxis is differentiated from other audience-buying platforms already developed by its rivals, including Havas spinoff Adnetik and Interpublic's Cadreon, but it claimed it would house "the world's largest pool of audience profiles in its proprietary database and reaching more touchpoints than any other solution in the industry." It will initially launch in 11 countries across North America, the U.K., and Australia and expand into to other markets this year.

The WPP unit said it is launching Xaxis in recognition of the "rapidly growing importance of audience-buying" systems that enable advertisers and agencies to target discrete audience profiles online, in mobile and other emerging media. Interestingly, the GroupM announcement stops short of explicitly discussing plans to bring the audience-buying platform to the television marketplace, even though most of the other major agency holding companies have said they plan to add addressable TV buys as the data and targeting systems become available.

That's noteworthy because GroupM has a stake in addressable TV advertising developer Invidi Technologies -- and GroupM global chief Irwin Gotlieb is on Invidi's board.

"By reaching only the most relevant audiences via a variety of media platforms -- display advertising, mobile ads, video ads and paid social media -- Xaxis delivers dramatically improved performance at lower cost than other industry solutions," GroupM asserted in a statement.

Brian Lesser, global general manager of WPP's Media Innovations Group, was named CEO of Xaxis.