YouTube is expanding in-video ads to YouTube partner videos embedded on other websites. “To date, YouTube has only run ads against partner videos on YouTube itself, and with people viewing millions of embedded YouTube videos every day, this meant that partners were not generating revenue from their views outside YouTube.com. But now, YouTube partners will be able to capitalize on their popularity across the internet and generate revenue from their content no matter where their video lives,”
Although this may sound similar to AdSense video units, this YouTube change is separate from AdSense, , and so no configuration within an AdSense account is needed. Revenue from these ads will be divided between YouTube and the YouTube partner providing the video content.
More info: AdSense Blog