In the ongoing effort to monetize, YouTube is now testing letting partners offer downloadable videos. Partners can allow downloads for free or for pay via Google Checkout, which requires a fee.
Partners testing the free downloads are educational, including Stanford, Duke, UC Berkeley and UCTV. Partners testing the paid downloads include users khanacademy, householdhacker and pogobat.
Here's a screenshot of a video by householdhacker. Notice the download link below the bottom left corner of the video.
Done right, this could prove quite lucrative for YouTube. Assuming this eventually gets opened up to more partners/users, it could prove quite the competitor for iTunes. But Google is much more open than Apple and many more users would have an opportunity to pursue revenue streams via YouTube.
In fact, bundled with today's download announcement is news that YouTube is now offering Creative Commons licenses for those of you out there who "get it" and don't mind sharing your work.