It only happens on Windows and I thought it worked on Windows 7 but I was either mistaken or there is an obscure option that needs to be toggled (something other than cleartype; this is a more serious aliasing problem).
The other sites you see trouble on were probably designed on Linux or OSX as well.
I see the same issue with other sites like: http://i.imgur.com/sbzmy.png
It only happens on Windows and I thought it worked on Windows 7 but I was either mistaken or there is an obscure option that needs to be toggled (something other than cleartype; this is a more serious aliasing problem).