Why is thread necromancy a bad thing?

[Arbane]

I don't understand why people posting to old threads is is a problem.

[Roland St. Jude]

Sheriff: The rules against thread necromancy serves many purposes among them:


1) The posting population is inconstant and discussions lose momentum. Reviving an old discussion is typically counterproductive because the originators have likely moved on, having lost interest in the discussion or concluded that it has run it's course.

That being said, the policy is actually *helpful* in fostering an active community -- new people can start, engage and mold their own discussions that previous posters have lost interest in (typically because they've been discussed to death) without having to defer to the conclusions of previous conversations.

But mind you, a duplicate of a recent thread will likely be nixed by the mods. But a discussion about ... the TV show Scrubs that started two years ago has little bearing on the attitude of current posters.
Azrael's explanation of the thread necromancy rules is dead on. We'd rather have new discussions start than revive old threads where many of the original posters have moved on. That being said, we also recommend linking to old threads on similar discussions, as they can provide some insight to concepts that had been raised before.
Necromancy also brings with it problems when there were technical issues in the past (such as those from the old forum software) all of a sudden appearing on page one and confusing people.

Depending on just how long ago the thread was started, many things could of changed.

The poster you are replying to may have left the boards. Everyone could have changed their opinions and no longer believe whatever was said in their posts. New books or rules/errata may have been published that make whatever was said in the thread obsolete.