When someone posts on a very old thread on a forum, it is called gravedigging.
Gravedigging is frowned upon because the topic of the thread is usually dead - hence the term gravedigging.
I understand that in most cases, but if so, why Doesn’t FR just delete them and make some space for themselves?
If the dead thread shows up on a search then it's open season to comment........
Chances are, the person who did the search then made a comment probably didn't even recognize the thread posting date.