As a young site we haven't had this problem much yet but in a fast moving world, things change quickly and what were once very good answers can become out of date. Due to our prominence in the search engines, it could be possibly harmful to leave outdated answers as they are. This is already a problem with people getting information from old blog posts and forum threads.
However, we have wiki style editing on our side so we can update answers as they become out of date or at least make it obvious that they are for a particular Ubuntu version.
What are the best practices for dealing with such situations?