Have followed this tool from the start and love it.
3 karma · joined September 11, 2014
Would recommend everyone have play with it!
An MVP is then created with the help of that seed investment and launched to help greater substantiate your product and attract further funding.
The Dropbox video is a good idea. It may not be a prototype but it created enough hype for them to show investors that there was a market and demand for what they were building. My only concern is that if you are creating a product in a new market you are potentially giving away a lot of your first mover advantage with that tactic.