Yahoo on Monday launched Yahoo Shine, a web site devoted to women.

Shine will be one of the highest-profile entrants in a rapidly growing field competing for ad dollars of women 25- to 54-years old.

"Yahoo has a lot of power in the women's market with their portal site," said Michael Greene, an analyst with JupiterResearch. "Yahoo has been very good at directing people where they want to go, and that has led to their success in finance, news, and sports."

The search company, which claims 40 million women visit Yahoo every month, is funneling women to its new site. But the company faces fierce rivalry. Sites such as Glam Media, which recently raised $65 million in VC funding, and iVillage, which also has a TV show, present much of the same kind of content--paid-for written content mixed in with reader comments.

Shine will feature content from lifestyle and entertainment publishers Condé Nast, Hearst Corporation, and Time Inc. along with user content and stories from its own editorial team, headed by Editor-in-Chief Brandon Holley.

"We think there was a void in the segment for a one-stop shop for women to find all of the information they need," Ms. Holley said.

The site features fashion and beauty, home, parenting, work and money, health, and food, among other areas.

"Yahoo is shooting at a pretty fat target," said Lisa Phillips, senior analyst with eMarketer. "But Yahoo already has a lot of this kind of content in various departments like Yahoo Health, so I'm still trying to figure out the distinction with Shine."

There are more than 100 million women online in the United States compared with about 93 million males, according to eMarketer. The research firm forecasts online advertising will grow to nearly $28 billion by 2008 and account for 8.8 percent of total U.S. ad spending.