Looks great! Have you considered linking this up to something like arxiv or other preprint sites?
Their job is a little bit easier because arXiv papers have the .tex source available, so you can use one of the various tex2html variants, instead of having to extract the paper's contents from a rendered PDF.
Our focus right now is on providing a tool folks can run it on whatever papers they have access to. For instance, some researchers might have access to documents that aren't available to the public. We want them to be able to run this against those.
That said as we expand the effort I imagine we'll eventually pre-convert things that are publicly available, like those on ArXiv, etc.