But, that doesn't actually answer your question, which I think is "Barely." I feel silly preparing PDFs for publication when I know that most people will read it on their computer, not print it out. Many conferences no longer even have an actual, physical copy of the proceedings, instead just giving out USB sticks with all of the PDFs. (Which is what we want anyway.)
I think it would be fantastic if there was a standard HTML5 template that researchers could use to publish their papers. There are Latex-to-HTML compilers, but I've never been impressed with the results. I think people outside of academia would be more likely to read our papers if they were in HTML rather and PDF.