Warner Music Group, the world’s fourth biggest record company, has signed an agreement with YouTube to put its copyrighted video and music on the site.

It’s YouTube’s first commercial partnership with any music company, and will see music videos, behind-the-scenes footage, artist interviews and other programming on the site.

Warner has also taken the unprecedented step of allowing YouTube’s users and video creators to integrate copyrighted music into their uploaded videos. A new software system developed by YouTube will identify content in uploaded videos so that royalties are reported and paid to Warner.

Revenue generated by advertising on the site run next to videos will be shared between YouTube and Warner.

The agreement comes shortly after one of Warner’s biggest rivals, Universal Music Group, took a swipe at YouTube and MySpace by calling them “copyright infringers” who owe the music industry “tens of millions of dollars”. The comments indicated that Universal may be planning to sue the sites.

“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 media forever."