Landscape page layout orientation should be the new standard
I have purchased three "books on PDF" in the last few months: not a bad deal since this costs publishers a lot less than producing physical books, so they tend to be about half price. One of these purchased PDFs has a landscape (horizontal) layout: what an improvement for on-screen reading! I wish that all publishers would take a clue and that people who produce papers as PDFs would also provide landscape options. BTW, I still have a few vertical (portrait) PDFs on my web site, but I am working on re-publishing them in landscape mode: I have switched to a Latex+some custom code writing system that produces HTML, and either format for PDF, but it is taking a while to converting some of my older projects to Latex.