I just noticed that the icons don't display properly in Firefox for Mac on one of my sites. The buttons are there, but some kind of markup is displaying instead of the font.
My site: http://www.sooverthis.com
Screenshot of the icons in Firefox: http://www.sooverthis.com/wp-content/uploads/2013/04/Screen-Shot-2013-04-25-at-9.31.23-AM.png
What's up with that? I don't see anything in Firebug that would be causing this problem.