My first reaction is that you'd basically be able to do what a webpage with javascript could do. On further thought, I realize that having tools like this low

My first reaction is that you'd basically be able to do what a webpage with javascript could do. On further thought, I realize that having tools like this lowers the learning curve for publishing interactive or formula-based documents. Hopefully this should lead to people producing documents that convey knowledge better. The main roadblock I see to this becoming more popular is how aggressive they are about keeping the format and viewer(s) proprietary.