One of the reasons many people in technical disciplines start using LaTeX in the first place is for the ease of typesetting mathematical formulas with it. In some circles, LaTeX-like syntax has become a de facto language for communicating math formulas in emails and other electronic communication.
In the past few years, there have been several efforts to implement non-TeX based intepreters for this "language." The most notable of these is probably MathJax (and its predecessor jsMath), but there are others; for instance, WordPress has a system for including math using TeX-like syntax.
Although there are a number of different interpreters for this "markup language" of TeX-style mathematics, there does not seem to be any standard for what such an interpreter should be able to do. Certainly it should not be required to provide the full functionality of (La)TeX, since this would be incompatible with settings such as Markdown and HTML. The lack of a standard seems likely to result in a number of different variations on TeX-like syntax that all vary in important details. On the other hand, if there were a standard, then it might be possible for browsers to start providing native implementations that run faster and produce higher-quality results.
Have there been any efforts to develop a standard for "TeX-like syntax" as a mathematics markup language?