I'm pretty sure this has been mentioned before by someone, but I'm still not sure how it is regarded as here.
The timeliness that mk feels is unnecessary, seems to encourage necroposting more, which would be quite interesting. Most forums and other community-websites absolutely hate necro-posting. In reddit it's just ineffective, since the post will never be seen.
Personally I think necroposting can be a good thing. Maybe a way to see if there's any new posts since a long time like RES does with comment threads would make it easier to see if a thread is being necroposted.
A common trait of someone necroposting is not to only bring one old thread back from the last page before deletion, but to fill up the entire first page with threads that only they seem to think have relevance to anything.