• by Joe Mandese  @mp_joemandese, March 12, 2004

Arbitron, a company best known for its radio ratings reports and for its efforts to develop a portable people meter-based measurement system, is expanding its presence in the field of media planning. On Thursday, the company said it acquired Marketing Resources Plus from a unit of VNU for $8.9 million in cash.

MRP provides media planning and buying software to local and regional advertising agencies. The systems are used to by more than 800 agencies and advertisers to plan both broadcast and print media.

The move is part of an aggressive diversification strategy designed to make Arbitron less dependent on the radio industry as a source of revenues. Recently, Arbitron announced plans to scrap its MeasureCast unit, a service that provided weekly and monthly ratings of Internet-based radio stations.

The company also has visions of expanding more deeply into the measurement of other media and even marketing research via a rollout and expansion of its portable people meter system.