[mort96]

Most people who write for the web probably do indeed write in something like markdown, which means they probably sprinkle in a bit of HTML for the parts which markdown doesn't natively support. I imagine a lot of blog posts written in markdown contain a few <table> elements, for example. Anyone writing math content for the web using markdown will have to either write the mathml directly, or write the math expressions in another language and manually compile it to mathml which is copy/pasted into the document. Maybe the CMS they happen to use will some day add native support for compiling latex, but that sounds rather unlikely.

[aplaice]

Pandoc and Mediawiki have been able to convert embedded LaTeX to MathML, for a while. Once Chromium supports MathML most CMSs will probably start providing suitable converters, and in the meantime MathJax will still work (and better, since MathJax's Native MathML output is faster than its CommonHTML one[0]).

[0] http://docs.mathjax.org/en/latest/output.html