Google announced today that the web publishers enrolled in its AdSense program will have the opportunity to increase enrich their content and altogether their income by embedding ad-supported videos from YouTube content creators.

The new service, called Video Units, will enable publishers to display relevant, targeted video content within a customized, embedded player that’s ad-supported. The videos are delivered via YouTube and for the moment Google is working only with selected content partners such as TV Guide Broadband, Expert Village, Mondo Media, lonelygirl15, Extreme Elements, and Ford Models.

The videos are user-initiated which means that the video will play only if the user has clicked the Play button.

The ads delivered are related to the content of the website and of the clip and they will be displayed as banners on top of the video window, as well as in text format on the bottom of the clip.

According to Google, the advertisers are charged on a cost-per-click or cost-per-impression basis.

The system will be benefic for every party involved. Google announced that AdSense publishers and YouTube content creators will receive a share of the ad revenue. The system which will go live during Tuesday is available in the US for English-language Web sites.

"Nowadays, Web site publishers realize that getting people to visit your Web site is only half of the equation. Growing your audience is important, but keeping your audience engaged and staying on your site longer is just as important, if not more so," Google Product Marketing Manager Christine Lee wrote in the corporate blog. The blog contains also a video example of how the Video units work.

The Video Units are just the latest Google effort to monetize the content from YouTube and to offer new channels to advertisers.

In August Google has unveiled its first ad format for YouTube.  The format enables a semitransparent ad to appear on a strip at the bottom of the video and it appears after a video plays for 15 seconds.

If the user who watches the video doesn’t click the ad it disappears up to 10 seconds later. The ad format is non-intrusive because the viewer can click to close the ad right away. In case he chooses to watch the ad, the main video pauses until the commercial stops.

Also last month Google launched Google Gadget Ads , non-traditional ad units with interactive, rich media capabilities which not only enable advertisers to target audiences in a flexible and timely manner via regular updates within the ad unit, but also allow users to engage with ad content in a way static ads haven't facilitated in the past. Gadget ads can incorporate real-time data feeds, images, video and much more in a single creative unit and can be developed using Flash, HTML or a combination of both.