Cannes, France (CNN) - Cannes Lions used to be a festival for ad agencies, then the clients started coming and now the content owners are coming. James Murdoch, Jeffrey Katzenberg and our own Jeff Bewkes, who heads up Time Warner, are all here this week.

Martin Sorrell, boss of the multi-billion dollar WPP group of creative agencies, talks of a new triangle of agencies, clients and media/content owners. In effect a new structure to the creative sector.

So where does that leave the likes of Facebook and Google, also represented here? Well, according to Sorrell, there is a place for them but it's not where they pretend to be. WPP is Google's biggest customer but he describes them as a “frenemy.” He says the tech companies including Facebook, Twitter and Microsoft are “masquerading as technology companies” when they are in fact media owners with their own channels.

Sorrell uses a parallel to describe his problem with his frenemies. He says it’s like Rupert Murdoch going to WPP's clients and saying they should only use News International channels like the Wall Street Journal.

Time for the 'tech companies' to 'fess up? Or is WPP under threat? Interesting that Sorrell is investing in content business at the moment...