TargetSpot, an online radio ad network, has signed up for measurement by Arbitron, the radio ratings firm, in partnership with online ratings firm comScore.
Under the terms of the deal, comScore Arbitron Online Radio Ratings will measure listening for TargetSpot's national network of 600 online radio stations, which are owned by various partners, including CBS Radio (now partnered with AOL), as well as Entercom Communications Corp.