I had a problem in viewing this forum. I managed to find a solution and I want to share the solution.

I don't know why but Opera showed some kind of symbols like pencils, rss feed icons and envelopes instead of letters in the forum messages (just the normal text in the messages, the code blocks, the titles and some signatures were OK). I read the html source and the css, tracked down the fonts used and substituted a font called "Ubuntu" with "DejaVu Sans" using an Opera extension called "Font replacement table".

I don't know why this happened, maybe it's because I uninstalled many fonts (mainly japanese and chinese, I'm using an old EeePC and the SSD is almost full).