AsciiMath – An easy-to-write markup language for mathematics
To everyone who says "why do we need this when we have LaTeX?" I ask the question "why do we need Markdown when we have HTML?"The nice thing about Markdown is that it's quite legible in its source form, which makes it less distracting to edit. Same deal with AsciiMath and LaTeX: AsciiMath is more legible in its source form which means that it has lower overhead during editing.One of these is more legible than the other:  (f'(x^2+y^2)^2)/(g'(x^2+y^2)^2)
  \frac{f'\left(x^2+y^2\right)}{g'\left(x^2+y^2\right)^2}

In my experience, most people who learn LaTeX don't do so until sometime around the middle or end of their undergrad career (certainly in Physics--maybe mathematicians learn it sooner). Earlier than that, people struggle with junk like the Microsoft equation editor. No big deal?