Pages with web fonts, like http://google.com/fonts, are not rendered correctly. All text that should be web fonts is shown with the default font. This is Firefox 20.0 on Ubuntu 13.04 with Gnome 3.8. - Starting in safe mode does not help. - neither does starting with a new blank profile. - There are no error messages in the Error Console. - Javascript is enabled. - not allowing hardware acceleration does not help. - the "Allow sites to use their own fonts" option is checked. - I am not behind a proxy. What else is there to check?