Firefox 4 on Linux gives a message at the bottom saying something like "WebFonts...

zootm on Dec 6, 2010 | parent | context | favorite | on: MathJax, beautiful math in all browsers

Firefox 4 on Linux gives a message at the bottom saying something like "WebFonts not supported, falling back to image fonts", meaning that the scaling examples look horrible and most examples are very fuzzy. Shame, looks neat otherwise :)