I'm running Ubuntu 12.04. In both Chromium and Firefox (ver 25), math.stackexchange.com fails to render the math formulas.
However, if I go to http://www.mathjax.org/, I see correctly rendered math formulas on the upper right of their home page.
Furthermore, if I try to post this question in meta.math.stackexchange.com I am blocked. (I'm not sure why I'm blocked. Maybe an admin can move this post for me, if necessary? And I apologize to the admin for the trouble.) EDIT: the login blocking and the math rendering appear to be related. It seems that meta.math.stackexchange.com and math.stackexchange.com are incompatible with HTTPS-Everywhere.
I have also tested this in Chromium ver 31 with no plugins and no special settings/options—and I experience the same math rendering problem.
In Firefox I made sure to whitelist mathjax.org and stackexchange.com in Ghostery and No-script. However, that didn't help. Even allowing scripts globally in No-script doesn't resolve the issue.
It seems that math.stackexchange.com fails with certain plugins or configurations while mathjax.org doesn't have a problem with these same things. At least that's my guess. I don't know what to conclude about Chromium not working. But I use Firefox normally anyway, so I don't care about Chromium not working.
Thanks for any help.