Citation from AdSense's official blog.

AdSense isn't just for ads anymore; it's also a place to get video content for your site -- and earn extra revenue at the same time.

We're excited about the launch of video units -- a new way to enrich your site with quality, relevant video content in an embedded, customizable player. Simply embed a snippet of code and have relevant YouTube partner content streamed to your site. You can choose categories of video to target to your site, select content from individual YouTube partners, or have video automatically targeted to your site content. Companion and text overlay ads are relevant and non-intrusive. To further blend the YouTube player into your site, you can also customize the color scheme and layout as well as choose from three different player sizes.

If you're looking to build "stickiness" with your visitors, show quality YouTube partner video on your site, and earn extra revenue along the way, and want to know more, then review our common questions about video units. You can also check out the video below to see how it works.