I don't think it's an issue with anyone's browser. Logically, it's just impossible. If it was a browser issue, then only people with the same exact browser and the same exact versions, updates, settings (etc) would be having trouble seeing the smilies. Yet, a lot of different people with a lot of different browsers are having issues with not being able to see the smilies.
Just as when we had the issue with not being able to log-in and/or stay logged in (when you check the "Remember Me" button), it has nothing to do with your browser. I have changed absolutely nothing about my browser and/or settings on my computer in over a year, but these problems for me have just come and gone. So, whatever is causing it is definitely not our browsers.
Could it be Java though? Perhaps.