Looks interesting! Is there a way to try it out on a webpage instead of PDF?
Nowadays a lot of bloggers/reporters keep running round in circles before coming to a point. I actually wrote a post related about this a while back [0]. With browser extension this can save lot of time of readers. Heck I would pay for such a service!
At this point you could print the page to a PDF and then upload it. A browser extension for webpages (as suggested by others) is a good idea! I'll look into it.