WEEKDAY AUDIENCE FOR ONLINE RADIO NETWORKS GREW BY 38% BETWEEN JUNE 2005 AND 2006
Midday Cumulative Audience Exceeds 3 Million Listeners

NEW YORK, September 20, 2006 – Arbitron Inc. (NYSE: ARB) and comScore Media Metrix, a division of comScore Networks, Inc., released today the online radio ratings for June 2006 and observed a sharp increase in Average Quarter Hour audience compared to the same month last year.

The weekday Average Quarter-Hour (AQH) audience for the measured online radio networks for June 2006 is 1,031,368 people age 12 and older listening Monday-Friday 6AM-7PM. 

The June 2006 audience to the five networks that were measured in the June 2005 report increased 38 percent, growing from an AQH audience of 743,500 in 2005  to an AQH audience of 1,022,400 persons age 12 and older in June 2006. Average Quarter-Hour audiences are the estimated average number of people who listen during any given 15-minute period within a specified daypart.

More than six million different people, age 12 and older, tuned to the online radio networks measured by comScore Arbitron during an average week in June, Monday to Sunday from 6AM–Midnight. The midday cumulative audience (Mon-Fri 10AM-3PM) for the six measured networks in June 2006 reached 3,279,400 listeners.

Persons 12+
Average Weekly Audience
June 2006
Geography: United States (50 States)

Note: Cume is defined as the number of different people who listen during a given daypart. Cume audience estimates for individual networks should not be added, because people who listen to more than one network will be counted twice. The reported audience for the total of the four networks is an unduplicated estimate of the number of different people who listened to one or more of the networks for a minimum of five minutes during the week.

* ESPN Radio was not part of the measured networks in June 2005.  They have been excluded from the comparison which shows an increase in AQH audience of 38 percent

**The Ronning Lipset Radio (RLR) Network is comprised of Yahoo Music, American Online’s AOL Radio Network, Microsoft’s MSN Radio and WindowsMedia.com, Live365 and Clear Channel Online Music.

The comScore Arbitron Online Radio Ratings service is based on a subset of approximately 200,000 U.S. participants within the comScore global consumer panel. Using proprietary and patent-pending technology, comScore passively and continuously captures the online behavior of these panelists, including online radio listening behavior. Subscribers receive Average Quarter-Hour and Cume audience estimates for 38 demographics and 15 standard broadcast dayparts. Each month, Arbitron publishes the average weekly audience for Persons 12+, Monday-Friday 6AM-7PM and Monday-Sunday 6AM-Midnight on its Web site www.arbitron.com.

Arbitron represents the comScore Arbitron Online Radio Ratings service.  For more information, contact Diane Williams diane.williams@arbitron.com or Bill Rose bill.rose@arbitron.com.

About Arbitron
Arbitron Inc. (NYSE: ARB) is an international media and marketing research firm serving radio broadcasters, cable companies, advertisers, advertising agencies and outdoor advertising companies in the United States, Mexico and Europe. Arbitron’s core businesses are measuring network and local market radio audiences across the United States; surveying the retail, media and product patterns of local market consumers; and providing application software used for analyzing media audience and marketing information data. The Company has also developed the Portable People Meter™ (PPM™), a new technology for media and marketing research.

Arbitron’s marketing and business units are supported by its research and technology organization, located in Columbia, Maryland. Arbitron has approximately 1,700 employees; its executive offices are located in New York City.

Through its Scarborough Research joint venture with VNU, Inc., Arbitron also provides media and marketing research services to the broadcast television, magazine, newspaper and online industries.

About comScore Media Metrix
comScore Media Metrix, a division of comScore Networks, provides industry-leading Internet audience measurement services that report-with unmatched accuracy-details of online media usage, visitor demographics and online buying power for the home, work and university audiences across local U.S. markets and across the globe. comScore Media Metrix continues the tradition of quality and innovation established by its Media Metrix syndicated Internet ratings-long recognized as the currency in online media measurement among financial analysts, advertising agencies, publishers and marketers-while drawing upon comScore's advanced technologies to address important new industry requirements. All comScore Media Metrix syndicated ratings are based on industry-sanctioned sampling methodologies.

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