According to newspaper reports the two companies – both owned by Publicis – have been testing both comScore’s and Nielsen’s services that measure the audience for online advertising.

SMG told The Wall Street Journal that it had chosen comScore because its services will be offered in more countries and because it will be able to collaborate with comScore to create new measurement products.

SMG’s CEO Laura Desmond told the newspaper: “It’s a multi-screen, mobile world and we need to be able to measure audiences fluidly and seamlessly.”