@anniereborn There is no problem responding to old threads, except for the fact that a lot of people stop following a Q, shortly after it has been answered, especially if a lot of members answer, because they feel like everybody has pretty much answered the question. Although, sometimes people do continue to follow all of the Q’s they’ve participated in. Also, a lot of past members that may have contributed to the thread, may not even be on Fluther any more.
Your best bet is to refer to an old thread with a new question. Example: I was just reading this question about Cooking from March of 2010 and I was wondering whether any of you folks like to host dinner parties.