Entertainment group GoFish  announced on Monday the launch of an online advertising and content distribution network, creating what the company said would be the third largest of its kind in the United States for web sites focused on children and teenagers.

Only perennial powerhouses Disney Online and Nickelodeon Kids & Family will have more combined online reach, said GoFish. The new network, which began in stealth mode last July, already gets 11 million unique, unduplicated U.S. visitors per month, the entertainment company said.

“We are reaching more kids online than you would get with your average Sunday morning television cartoon,” said GoFish Chairman Jim Moloshok.

The new network should be attractive to online advertisers looking to target the under 18 demographic, which increasingly wields purchasing power. Packaged Facts estimates American kids will influence $21.4 billion in spending by 2010.

The market research firm also estimates that American teens have a total income of $80 billion, and their parents spend another $110 billion on them for such things as food and entertainment.

The new network will include GoFish’s web site in addition to online game sites Miniclip, Cartoon Doll Emporium, and Hallpass, and teen social-networking site Rocketon, among others.

GoFish President Tabreez Verjee said besides advertising he also aims to use the network for distribution and syndication of online content. He said they are working with writers and creators to make characters that will be born on the Internet and will be catered to an online world.

The San Francisco company in January announced a content deal with several MTV Networks brands, including MTV, Nickelodeon, and Comedy Central, in which the two groups will share advertising revenue. But that distribution deal is so far limited to GoFish’s web site only, though Mr. Verjee said he would like to expand it to cover the entire network.