I wonder when search engines will start indexing MathML. I spent a good part of college trying to figure out exactly what to search for in Google while working on problem sets and being able to search expressions would've saved some late nights.
The problem is context. A formula means nothing without it. Identifying the correct context (or even just the most likely one) for a formula is Not Easy.
Different fields within maths, engineering & physics frequently reuse names and symbols to mean different things, so formulas which look the same can have completely different meanings. And as you alluded to, formulas which look different can end up meaning the same thing.
MathML is split into presentation markup and content markup. The presentation markup describes the rendering of a formula; the content markup describes its semantics. If anyone actually used the semantic markup, it could help with this problem.
