The technology to deliver that video well isn't do-able in a week. Socialcam will probably benefit from the years of experience the Justin.tv team has dealing with problems related to efficient storage and delivery of video content.
It's hard to believe that companies that share photos from phones that do video haven't been working furiously on supporting video. Now they'll just intensify their effort.
When Flickr was king of social media, they tacked on support for uploading video as a knee-jerk reaction to the surging popularity of then-nascent YouTube. It never recovered, and now YouTube is king of the pile. You'd get more views of your photography collection if you stitched it together in iPhoto and set it to Nickelback's whatever dumb hit song and uploaded that to YouTube.
The photo sharing and now video sharing market is still very young. I would not assume that any one of these companies has won. There is still plenty of room for innovation.
