Sometimes I just want to review a topic which I have ever read before,but there is no convenient approach to find it unless it is still appeared in "recent actions".
It seems that the only way to view old topics is to memorize who post it and to find the topic from his profile page.
"you request site:codeforces.com"
in google
Also http://www.google.ru/search?q=find+old+topic+site:codeforces.*