For me the answer is: sometimes.
If I want to keep the conversation intact for context, then I'll resurrect and old thread. But I try to do it in such a way that is clear I'm adding to an old conversation.
However, I see a lot of users reply to an old IMDb post as though it were new and that person will be reading it. It seems odd. I always feel like I want to reply, "you know that's from IMDb and they won't see it, right?"
I don't like it since it can be used to bury current posts. A crazy jerk on my IGNORE list replied to my post on an obscure movie with some nonsense that was unrelated to my post and followed that up with more unrelated nonsense replies to posts from fifteen and five years ago. The other posters from five/fifteen years ago were from IMDB so there was no point in replying to them. I think it's cool to see the old posts but it would be better to archive posts after five years of inactivity. The crazy jerk didn't even watch the movie but was posting about how great these conversations from fifteen/five years ago were. I noticed another wacko replied to a post from five years ago with pointless grammar corrections.
shareThere are a some jerks around I get that, but the site is meant for conversation.
Pay no mind to weirdos joe
I support conversations/debates but that requires participation from two or more parties. I don't like off-topic replies to old threads since most of the participants from five/fifteen years ago were never on this site. These old threads are imported from IMDB. I think a reply to an old thread is okay if it's related to the topic BUT I prefer starting a new thread.
The IGNORE feature on this site is flawed so we can't really ignore the people who annoy us.
I answer some really old posts because I like to put my view forward. The OP won't see it but other people will.
shareThe same. Sometimes you just feel like answering. It's not like that person who actually wrote it is the only person with that opinion or question. Sometimes I get an interesting reply to something I wrote in one of those old IMDB threads, so it's not a waste of time.
shareIf you have something to add or a question, i'm not bothered by it.
People will give you a hard time for creating a new post about an old subject too sometimes. I don't really care either way, if they have a reason to bring it up.