Reply To: What can .epub do that .pdf can't?

I like to think of EPUB as a Word document: it's basically a linear flowing document in which you can change the font, the type size, margins, and so on. There are, however, fixed layout EPUBs (just like there are word docs that appear to mimic what you can do in InDesign).

Looking forward a few years, there is a reasonable chance that a LOT of what people are doing in PDF will be done in EPUB. But it's going to take a while to get there.