MathJax [1] is now enabled site-wide as an opt-in preference. You can now see beautifully
rendered, accessible, copy&pasteable and standard-compliant (MathML) formulas on
Wikipedia, replacing the old TeX-rendered PNGs.
To enable MathJax on Wikipedia or any other Wikimedia project, go to your preferences >
Appearance > Math and select "MathJax (experimental; best for most
browsers)". A big thanks to the MathJax developers and all the folks who helped
deploy it. [2]
Dario
[1]
http://www.mathjax.org/
[2]
https://bugzilla.wikimedia.org/show_bug.cgi?id=31406