Nielsen broadened the reach of its Online Campaign Ratings initiative with the addition of more than a dozen online ad partners as part of the measurement firm's goal to bring a GRP to online ad buying. Beet.TV talked to Tom Acquaviva, Senior VP Strategic Accounts at Nielsen at the Adap.TV conference in New York and he shared more details on the initiative.Nielsen first launched its Online Campaign Ratings tool in 2011 with Tremor's Video Hub, and the latest expansion will enable additional online ad vendors to integrate the Nielsen tools into their platforms. The online ad partners include Adap.TV, AudienceScience, DataXu, FreeWheel, Innovid, Jivox, LiveRail, SET, TubeMogul, Turn, VideoHub, Videology, Vindico, and Zedo.The value of a common currency across TV and online platforms is that it can enable scale and also make it easier for ad money to move between TV and online, Acquiviva says to Beet.TV. "GRP is a metric that had been used by brand markters for 30-40 years and it's a reliable metric and one [buyers are] comfortable with," he says to Beet.TV. Online ad vendors, media agencies and brands alike have focused on the need for shared currency for some time. In the last year, many vendors and agencies have started to make strides in testing new tools and metrics that may help standardize ad buying across traditional and new mediums. The Nielsen initiative also allows for real-time changes to campaigns. "Both buyers and sellers can understand how the performance is going on a particular campaign and make the right in-flight adjustments," Acquaviva says.