Only authorized clips will feature the links, which show up on a small bar under the video. Once users click, they will be taken to an artist's Amazon MP3 or iTunes page, where they can buy and download the music. The same goes for clips of games like Electronic Arts' Spore, which is available for download at Amazon.com. Meanwhile, record companies and artists that monitor YouTube for authorized (and unauthorized) content usage can enable the "click-to-buy" ads on their own clips, if they choose.

On the Official Google Blog, YouTube product managers said that part of the motivation for developing the eCommerce platform came from the users themselves. "When you view a YouTube video with a great soundtrack, you often see comments from YouTube users asking about the name of the song and where they can download it," said Glenn Brown, strategic partner development manager at YouTube. "Or when users watch the trailer for an upcoming video game, they want to know when it will be released and where they can buy it. Today, we're taking our first steps to providing YouTube users with this kind of instant gratification."

The ads are currently only available in the U.S., but YouTube plans to expand the program internationally in the coming months. The platform is also slated to cover other products, including movies and books. "This is just the beginning of building a broad, viable eCommerce platform for users and partners on YouTube," said Thai Tran, YouTube product manager. "We'll be experimenting with the UI over time to make sure this works for our community, and we'll continue to innovate based on your feedback."

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