I only bring it up b/c if your goal is to turn pdfcrowd into an app that people would pay money for (and I would be one of them), solving that problem would go a long way towards achieving it.
Solving it perfect is non-trivial (I've known entire PhDs to be spent working on a small subset of the problem). There are a number of products/projects that solve it to some extent (techniques include absolute positioning & making sweeping assumptions about what constitutes a paragraph) - would this be enough for you to consider paying for, given that their assumptions/workarounds might produce HTML files that aren't quite to your 'taste'?
There already many apps and pieces of software that charge for the feature he already has so I don't see why it is a requirement for him to monetize. It definitely would be an easy feature to charge for but I think what he has already has potential.
