Here's a screencap. The url, if you can't read it, is http://www.mcclatchydc.com/

Definitely does not normally look like that in any way.

I went to the link and it displayed normally to me. And those characters in your screenshots are combination of Chinese as well as symbols, which have no meaning whatsoever. Have you done a virus/spyware checks of your PC to see if it catches anything? That Chinese social media website might have installed some spywares in your PC when you were there.

I've run some scans, but it's entirely possible that something slipped through. I have a pretty robust firewall, but the problem is obviously something on my end. I'm wondering if it has to do with an interaction between something on my computer and the hosting or architecture of the pages I've visited. Most sites load fine, but there have been two or three that do this.

Also, because it's only Firefox, is there something about Firefox that would be vulnerable where Chrome isn't?

Please read this article to see if it helps. The Chinese website might have somehow changed your Character Encoding settings and didn't revert it back to your original one:

http://chinesehacks.com/software/change-the-character-encoding-for-a-website/

Here's another one, but quite lengthy though:

http://forums.mozillazine.org/viewtopic.php?f=38&t=1988057

Yeah, changing the character encoding to universal did it... for most sites. At least now I'm starting to see where the problems arise. Thanks!

EDIT: Everything works now. There are two places where you can set default character encoding (View>character encoding and options>content>fonts&colors>advanced>character encoding), and the two didn't match up on my computer. One was UTF-8 and one was UTF-16. I don't know if it's coincidental that the last problem site displayed properly after I changed them to both match, but it's probably worth noting.