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MEDIA METRIX RELEASES THE TOP 50 AT HOME AND AT WORK DIGITAL MEDIA AND WEB AUDIENCE RATINGS IN THE U.S. FOR SEPTEMBER 1999

Traffic to Sports, Weather and News Sites up in September

New York, NY, October 20, 1999 -- Media Metrix (NASDAQ: MMXI) today released the Top 50 At Home and At Work combined Digital Media and Web audience ratings in the U.S. for September 1999. Media Metrix also reported a significant increase in unique visitors to top sports, weather and news sites from August to September.

User traffic to the top five weather domains on the Web rose sharply as the hurricane season blew in:

Top Weather Sites, September .99, Percent increase from August to September

Digital Media: includes users of the World Wide Web, proprietary online services, and/or other ad-supported digital applications such as e-mail services and CD ROM.

Unique Visitors: The actual number of total users who visited the reported Web site or online property at least once in the given month. All Unique Visitors are unduplicated (only counted once) and are in thousands.

About Media Metrix

Media Metrix, Inc. has active operations across multiple regions of the world including the United States, Europe (under its majority owned subsidiary MMXI Europe), and Australia. The company utilizes its patented metering methodology to measure actual Internet and digital media audience user behavior in real-time . click-by-click, page-by-page, second-by-second. Media Metrix provides leading advertising agencies, new and traditional media companies, e-commerce marketers, technology companies and financial services companies with comprehensive coverage of all digital media. For more information about Media Metrix, please visit www.mediametrix.com.

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