How do we make PDFs reflowable?

I read news that Adoble released some Mobile SDK that would make PDFs reflowable. Is such technology out yet? Does involve converting a standard PDF to a reflowable? If so, how do we do it? Or is it based on a software that dynamically reflows content?

Reflow the contents of Adobe PDF documents

In the steps that follow, you'll learn how to create a reflowable Adobe PDF document from a Microsoft® Office 2000 for Windows® document.