This video is intended to explore reliable, cheap, safe, and alternative means of reaching orbit, and of course get the idea out there in peoples heads. I also forgot to mention in the video that you can provide greater lift capacity by stacking the balloons on top of one another.
This launch platform features ...
1: Less gravity - because you are farther away from the surface of the earth
2: Less atmospheric drag - again because of the high altitude there is less atmosphere
3: After launch the balloon can release some gas and float back down for reuse.
4: If the rocket fails during lift off it has plenty of time to deploy parachutes for a recoverable landing. Something a land based launch cannot provide unless the rocket has already launched and is well above the ground.
5: Cheaper - The size of the rocket can be reduced due to the fact that it not as much fuel is required to propel it into space. The cost of a balloon is cheaper then the cost of more rocket parts.
6: The shape of the balloon reduces drag and drift from high altitude winds and can be engineered to act like a primitive wing to assist with stabilization by flexing and twisting to match wind conditions.
Note to nasa: You can't get any farther from space before you start launching from under ground. The locations where nasa and other organizations launch are often close to sea level, making it all the more difficult to achieve a successful launch.