Has anybody ever taken a look at the technology behind a site like http://www.signnow.com?

I'm interested in the tech that was used to develop this. It looks like something called FlashCanvas (maybe written like Flash Canvas) was used to develop it along with some JS. I'm not really sure and I need a direction to get started in. I'm fairly good at reverse-engineering and figuring out how these things work, but if someone has had experience developing something like this, I could really use some input.

Much appreciated!