By the way, I've also been reading up on PDF format in Wikipedia and it seems that what is described generally in this board that PDF is a poor format for digital readers seems to be patently wrong. The problem has to do with how the PDF is created. PDFs can be created with accessibility in mind (
see PDF accessibility). If it is properly created for screen readers, I think PDF flow issues would not be a problem. Various items in the PDF document can be tagged (e.g., as paragraphs, etc.) to aid.
Seems to me that PDF is a very flexible format which however has not been taken advantage of fully for the digital reader world.