LOS ANGELES (AdAge.com) — Advertisers got what they wanted in 2007: They started paying for ads based on ratings for commercial breaks, not the shows the ad interrupted. But they still want more. Since that time, marketers and ad buyers have tinkered with the idea of introducing other, more-granular ad measurements to the mix. As marketers prepare to negotiate with network ad sellers for the upfront, which metrics are ready for prime time and which ones still need to be tweaked? Ad Age checked in with key players and researchers to see what new ideas might be on tap for next season.