Do you tag your topics?
Since recently we have a new capability for categorizing forum topics: tagging. Our forums are quite general, so for example a "GNU/Linux distributions" forum is for all distro-specific questions, from Slackware to Ubuntu, but thanks to tagging you can specify a specific tag for a question which is about Ubuntu and one which is about Slackware. For example, if it is a question about Ubuntu package manager (apt-get) then you can tag it as "ubuntu" and "apt-get" or maybe also "synaptic".
I recommend you use this feature as it is quite simple and yet it allows for more easy surfing through forum topics using the tag cloud at the bottom of the forum index. It allows people to more easily find topics related to a specific thing.
I'm thinking maybe we should implement some sort of an incentive or reminder about this feature so that it is used more. Suggestions about that are welcome. 
How do we put a tag on a thread?
Use the "forum tag" field in the category section of the submit topic page. The info is on the help page.
However I have to issue an enormous apology. After all the talking about forum tagging I find out now that permissions weren't properly set for non-admin users and hence you never even saw that forum tagging box. Gee, why do I always fail to check these things.. I set the general permissions and then miss all those rigorous category settings. :\
My apologies.
I just tried tagging a thread and when I went back to edit it, the tag was never there again.
The tags were created but for some reason there were a lot of "don't panic" tags created of which these two work:
http://www.nuxified.org/forum_tags/dont_panic_1
http://www.nuxified.org/forum_tags/dontpanic_0
I've tested creating a new topic with an ordinary tester account with a tag and then editing that topic and the tag was there, all was normal.
I'll test it as a moderator user in a bit and if everything turns out fine then I'm not sure what's the deal.
Tested it as normal mod user and it works normally as well. Could you try again with other threads that you opened and without spaces or apostrophes in the tag?
I never tend to open new threads.