Here is their introduction:
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. (More)
I still don’t know how this thing works. I checked my Adsense account and there is no settings for video unit yet at this time. Let’s learn more about this new feature by reading their FAQ here.