I just found out that WordPress.com supports LaTeX math markup! It’s pretty easy to use.
(For lack of any ideas original or even remotely profound!)
Now I have to go back and fix all those previous posts… I’ve been pretty lazy about typesetting and usually just used plain letters and computer-style operators (* for multiplication, etc.). I think I’ve used the var tag a couple of times but not consistently.
More info at http://en.support.wordpress.com/latex/.
EJRH 