Congrats to everyone at Yahoo! for the successful acquisition of Jumpcut. Jumpcut is a a social media service.. in a sense. It is similar to Motionbox which I briefly looked at, but allows users to upload not only videos but music and pictures as well. After you've uploaded some media you can "remix" and mash it up as you please, or leave that up to the viewers.
I think Jumpcut is the perfect addition to the Yahoo! lineup. Yahoo! Video is still maturing, so hopefully the Jumpcut guys can give them a few pointers and perhaps integrate features amongst various Yahoo! properties. Jumpcut's interface reminds me of Flickr's - with tags, video details, forward/backward navigation and similarly styled comments. Flickr aficionados shouldn't have a problem adapting to Jumpcut.
Now that Jumpcut is part of the Yahoo! family, Yahoo! is really the one destination for all your social media needs - Flickr has over 2.5 million users and del.icio.us recently announced their millionth user. But then again, I am biased.. I did work for them.