Nearly 150 local TV stations launched on Monday a network of websites that will compete for national advertisers with the news sections of the Internet portal giants.

The aggregated online advertising network, called the Local Media Network, includes major market stations WABC in New York, KABC in Los Angeles and WLS in Chicago, all owned by the ABC network, as well as websites from other broadcast groups, such as Liberty, The New York Times and Meredith.

ABC is the only major network that owns stations within LMN.

ABC and New York-based WorldNow, which provides Internet technology for more than 200 local media sites and built the LMN advertising platform, formed the network to compete for national advertisers with Yahoo Inc., Microsoft Corp.'s MSN, America Online Inc. and Google Inc.

LMN will pitch advertisers on its ability to target local markets as a whole, in groups or individually, Allison Bodenmann, executive vice president of national sales for WorldNow, said. The network has a combined monthly traffic of 20 million unique visitors.

"The network will attract advertisers the stations wouldn't necessarily be able to hook up with and sell sponsorships on their own," Bodenmann said. "We're only talking to national advertisers, so we won't be competing with local TV stations for their ad dollars."

LMN will share advertising revenue with the local TV stations.

While the Internet portals have entered local markets by offering visitors the ability to search for products and services, LMN stations are more closely tied to the communities they serve, offering news, weather, sports and information on community events and activities, Bodenmann said. In addition, the sites have expanded into specialty areas, such as cooking and healthcare.

"They're the only place where you can get scores on high school football games," Bodenmann said.

National advertisers can choose to run ads tailored to a local audience, Bodenmann said. A food company, for example, may choose to run ads in conjunction with supermarkets in specific markets.

Local search has become a big draw for advertisers on portals, because of the number of web surfers it draws. AOL, for example, says 20 percent of its online look-ups are for a product or service near a person's home.

The portals, however, still have a ways to go in satisfying visitors. While local search is in high demand, it also draws the most complaints from consumers, who often find that the results don't match their needs, according to web tracker Keynote Systems Inc. In going after advertisers, LMN is sure to point out the growth in visitors at TV station websites. The number of unique visitors at sites of WorldNow clients increased to 11 million in January of this year from 7 million in the same month a year ago, according to Bodenmann.