HipHop was facebook's attempt to make php faster. They tried to convert source code parts to native machine code, which worked quite well. Now they work on another (but quite related) approach called hhvm (hiphop virtual machine), which is even nicer. I installed it on a ubuntu vm and it runs like a charm.
I love markdown and easy markup languages, because in my holy opinion word is some sort of overkill - Far too many options you will never need or use. So I was not able to express complex equations with markdown till now. I found a nice lib called *MathJax* and will show how to use it.