Again, the problem is NOT a problem of AUTHORSHIP. Authorship is easy. It's a problem of DISPLAY. And it is a serious and important problem to be solved. The web was invented to share scientific information. Education on the web is huge--and growing. Academic publishers, mathematical software, and software shims that display math in a browser all use MathML extensively. It's a ubiquitous technology precisely because it fills a need in the industry, and it fills it well. What's more, MathML is important for an accessible web.
PDF is clearly not good enough for digital consumption. PDF is great for print but totally sucks for screens. MathJax is amazing (as are the people behind it), but it is a huge, complicated, and inefficient solution to the problem of math in the browser. The author of the linked article in the submission works on MathJax professionally and is advocating MathML support in the browser. That should tell you something. (In fact, MathJax itself uses MathML both internally and as an input/output format.)
As a mathematician and hobbyist iOS developer, it really sucks that so much great mathematics software is GPLed. You can't port Octave, for example, to the iPad as its license is incompatible with Apples terms. I'd love to see this kind of stuff on my iPad. I'd even write it myself! But nope... A few great non-GPLed mathematics packages that have made their way into the iOS ecosystem. There's a Reduce implementation, for example, that looks really nice.
And while I'm rambling (sorry), LaTeX on mobile is just in shambles. I mean, it's in shambles on the desktop, too, but it's nearly impossible to do on mobile. It needs a rewrite. Period. But the mobile dev community has done a really great job getting as far as possible with what we have with LaTeX.