m-dashes and acronyms

This thread has been going a little while now. And a lot of it has 
presented acronyms and abbreviations with no mark-up. Perhaps an 
important question to ask is "How are those who use screen-readers, 
braille printers, etc, understanding the discussion so far?"

As a sighted reader, it has not presented many problems to me. Is that 
the case for others?

Charles McCathieNevile