Vodpod is social bookmarks for video’s, grab them from any video site and bookmark them in your vodpod, show them in a widget. Not only do you have a user space, but you can also join group pods.
I bookmark audio files in Podchains (you can bookmark any media file), but it won’t play within Podchains, you also get a widget, and space to host your own media URL’s from the media files on your PC.
With Podchains you actually bookmark the file, with Vodpod you just bookmark the web page the video box is hosted on, so you are not actually saving the media file itself.
See my post, The Podcast Listener, where at the end I link to lots of ways to download video URL’s into video files…also check out similar video social networks.
Here’s an example post from the The Chris Pirillo Show, notice that you can download a YouTube clip directly from the post, it seems to use Google Video somehow, not sure how this works.