Newly formed network the CW continues to gain traction among TV stations across the land. The network is a joint venture formed from CBS Corp.'s ( CBS) UPN and Time Warner's ( TWX) WB, along with Tribune's ( TRB) station group. When the new network was announced in January, the CW had about 50% broadcasting coverage between various CBS and Tribune stations. In two months that figure has climbed to its current level of 66%. The CW will take the best of both UPN and WB programming. Independently, both had been losing money for their parent companies. Leaders of the venture hope that by saving the best content from each, and streamlining operations, they can turn two uneven networks into one powerful force that's more attractive to advertisers. Last month, News Corp.'s ( NWS) Fox decided that its stations would go it alone and quickly announced the formation of the MyTV Network, a play that changed the competitive landscape yet again and left local station owners to decide which new network horse to run with at the affiliate level. The CW announced Friday that it has signed up an additional 18 stations and can now claim national coverage in 19 of the top 20 markets and 26 of the top 30. The big push comes as the annual TV upfront season, when advertisers make commitments to the networks, approaches. "These newest members of the CW affiliate family represent an outstanding group of broadcasters, and we're very pleased to enter into these long-term affiliations with each of them," said CW chief operating officer John Maatta. "They join a growing lineup of stations that will reap the rewards of being a part of America's newest full-service network -- a network which has the unique advantage of launching with well-known, star-driven, successful and eminently saleable programs that are magnets for our target demographics." The CW launches in September. On Friday, shares of CBS Corp. were trading up 9 cents to $24.31, while Time Warner shares traded up 2 cents to $17.13.