First off, that is an amazing website -- to me it feels a bit like the modern day equivalent of a page filled with blink tags and animated gifs
Having a shrill pink and green banner that takes up half the screen, and things sliding in and out every paragraph, shouldn't take away focus from the idea though, which I really like.
Two things that worry me:
There is a tendency that developers and users speak slightly different languages, and users can sometimes have a hard time expressing what their idea is, in terms that developers can understand. Also, as soon as you've managed to communicate the idea to the developer, won't something like GitHub work better?
And what would the legal status be of the app, what if the developer wants to monetize the amazing app he wrote? what if the user who had the original idea does?
Btw, from the forum: