ENWorld has implemented a feature that I think would be great over here. To see how it works, just visit any thread there, and assuming you have an account, click the button at the bottom of a post that says "Fork to new thread". Result: you're now editing a post in a brand-new thread whose default subject is "Forked Thread:
". Already filled in for you on the first line of your new post is
"Forked from: "
and then quoted text from the post you forked from.
The benefits that I'd hope to see from this feature include- reducing thread drift
- making it easier to locate discussions of interest
The only concern I have about the given implementation is that users may be likely to leave the default subject. I think it'd be better to leave the subject line blank so the poster has to give some thought to a subject.
With sufficient scripting magic, it'd be even better to have supplementary text added to the subject. So, e.g., I fork from a thread called "D&D" and give my new thread the title "Why Bards are great". On the forum page, this would be displayed as "Why Bards are great (forked from thread: "D&D")".
It'd be even better if a post from which a new thread is "forked" would get a "forward link" inserted that points to the new thread.
But really, I'd be happy to just see a copy the ENWorld implementation. It might be a good idea to wait until we've observed how well it's worked in practice over there for a while, though.
I've seen a few accidentally forked threads since they started it, from people who clicked it on accident, perhaps while aiming for the quote button.