As a University, we have used MathML to deliver typeset mathematics over the Web for many years. Until the advent of Design Science's dramatically expanded high-quality support for enabling technologies in its MathPlayer IE plugin, we were unable to support the many Americans (and others around the world) who, through no fault of their own, require special technologies to use the web at all.
Microsoft has provided excellent support for these enabling technologies within its more recent Windows operating systems; however, because of the quite recent lack of support for a corresponding delivery of web-based mathematical tools, we are forced to revert to19th century methods (e.g., e-mailed paper copies) to accommodate people who clearly deserve appropriate consideration and better treatment. (Among other uses, we have been providing on-line tests to people all over the world using MathML technologies.)
Current alternative technologies (e.g., MathJax) for displaying MathML are too slow and incomplete to be taken seriously, AND THEY PROVIDE NO SUPPORT WHATSOEVER FOR THE MANY PEOPLE WITH SPECIAL NEEDS.
We truly hope that the current situation (i.e., an IE which simply no longer supports MathML) can be addressed in the near future.