I have some good news and some bad news.
First, the good news is HTML5 includes MathML and has been embraced by all browser vendors.
Now the bad news. MathML support is broken in IE9 and we see no evidence that Microsoft will fix this problem unless they are made to understand how important MathML support is to the STEM and education communities. MathML is also an important key to insuring math accessibility to the blind and sight-impaired, as well as those with certain learning disabilities.
While we applaud Microsoft for promising to support HTML5 with Internet Explorer 9, we hope you will join us in encouraging them to fix the small bug that is currently preventing MathML from working in HTML5 pages. Please publicize the issue with whatever resources you have: personal blogs, tweets, forum posts, comments on other people's blog posts, etc.
Read the whole story: MathML in HTML5: Internet Explorer 9 is Broken.