I don't really believe in the concept of a "dead thread". They don't have any levidity or rigor so they can't actually be "dead". Threads don't become pale or go into a coffin.

Awful situation happened to me just recently. It was a motorcycle forum. A thread had been resurrected from the past and I noted as I went through the responses that many of the people replying were in fact now DEAD. It was a little spooky but left me with a lot to think about.

The only problem with "dead threads" is that the original people can't reply or correct some bad ideas they used to have.