Why would anyone even want this? The most important part of recording is the ability to have multiple takes, which is hindered if every take is to be uploaded at the same time. All other use cases can be covered by streaming your desktop.
how do you stream your desktop?
Use OBS http://obsproject.com/ (Open Broadcaster Software) and stream to a website like justin.tv/twitch.tv.
It's also possible to save to a file, so it's easy to do screen capture for anything else too.