Nielsen and comScore are courting brands such as Procter & Gamble, Unilever, General Mills and Kraft Foods as they seek to popularize rival systems for rating online ads. Nielsen received Media Rating Council accreditation for Online Campaign Ratings, a tool that uses anonymous Facebook data to provide advertisers with demographic data. ComScore is closing in on accreditation for Validated Campaign Essentials, which includes a "viewability" measure to ensure ads are served in places where they're actually visible to consumers.