My Firefox upgraded this morning to version 3.6.13, and I've noticed a number of striking differences; I'm wondering if it is me, or if the site has somehow also changed coincidentally at the same time.
This morning, I've been having some trouble with very slow processing of math text (text within dollar signs), taking up to a minute to occur, and the look of the math text has changed considerably from the way it looked yesterday. (Added: I note that the math fonts in MathOverflow still look the same as they did yesterday). Added: When processing after a reload or hard-refresh, it ends saying in a little box on the bottom left "can't load web font TeX/Math/Italic".
Here's a screen shot:
It seems that Firefox is unable to load the math fonts for some reason; the messages flash too quickly to catch all, but I just did a screenshot that captures the last one. it's in the bottom left corner of the webpage:
The displayed equation looks different from what equations have looked up to now, and the way they look on MathOverflow; e.g.,
I'm running on Ubuntu 10.04.
UPDATE: I followed the link to the MathJax page for font help, downloaded the STIX fonts and installed them locally. That seems to have solved both the time and the display problems. So it seems clear that the problem was that somehow I was not able to load the web-based fonts.
UPDATE 12/12.2010: It seems that the MathJax folks have fixed the problem on their end. I uninstalled the local fonts in my Windows machine and everything seems to work fine now; I'll try it in my Ubuntu machine tomorrow.