I have an old client who contacted me to see if I was familiar with zmags. I wasn't. According to their web site it's "a digital innovation that transforms static PDF files into a dynamic and user-friendly presentation." My clients publishes a number of magazines, some weekly and this is a way to convert the PDF format into something that people can flip through. I find it unwieldy and more importantly don't think the search engines can index this format. They want the search engines to be able to find back issues and articles, but so far the magazines they've posted haven't appeared in the index.