Sometimes you may want to explain some algorithms or principles with beautiful formulae in your blog. How to do this? Edit them in Microsoft Word, take a screenshot, crop it and put it in the blog post? When you finish your article and find out that you missed a symbol in the pictures - oh man, gotta repeat that again? Stop using those images now! A beautiful math display engine - MathJax allows you to code math like a coder.
$$\mathcal{C}\phi \delta e \mathfrak{M}\alpha th \mathit{I}n \mathcal{H}ex\sigma \mathbb{N}o\omega!$$