ComScore, which measures consumer web activity, and Rentrak, which monitors set-top box data to determine how consumers are watching television, said Tuesday that they would merge, with Rentrak becoming a subsidiary of ComScore. The combination could give rise to a strong competitor to Nielsen, which has long been the dominant company providing audience measurement to media companies and the advertisers who support them.
Source: ComScore Buys Rentrak In Bid To Conquer Media Measurement | Variety