Under a revenue-sharing deal announced Monday, New York-based Warner Music has agreed to transfer thousands of its music videos and interviews to YouTube, a San Mateo, Calif.-based startup that has become a cultural touchstone since two 20-something friends launched the company in a Silicon Valley garage 19 months ago.

Perhaps even more important for YouTube is that Warner Music has agreed to license its songs to the millions of ordinary people who upload their homemade videos to the website.

"We are very excited," YouTube co-founder and CEO Chad Hurley said in a phone interview Sunday. "This is a real landmark for our company."

Warner Music ranks as the third largest recording company in the United States with annual revenue of 3.5 billion U.S.dollars.

Besides it namesake label, the Warner Music family includes Atlantic, Asylum, Elektra and Rhino—a group that includes vintage recording artists like Led Zeppelin, the Doors and Ray Charles, as well recent hit makers like Linkin Park, Green Day and Faith Hill.

Privately held YouTube is hoping the Warner Music deal will serve as a springboard for similar alliances with other long-established media outlets looking to connect with the website's audience, which watches more than 100 million videos per day.

"Technology is changing entertainment, and Warner Music is embracing that innovation," said Warner Music Chairman Edgar Bronfman Jr. "Consumer-empowering destinations like YouTube have created a two-way dialogue that will transform entertainment and the media forever."

Many of YouTube's most widely watched videos already include copyrighted music, raising the specter of a legal showdown with record labels and artists seeking to protect their right to be paid for the material.

YouTube so far has been subsisting on 11.5 million dollars in venture capital, spurring predictions that the company either will have to raise more money or sell out to a deep-pocketed buyer as it tries to fend off increasing competition from Internet powers Google Inc. and Yahoo! Inc.