I know - that was my point.
Imagine there was a very good thread about developing C-41 as B&W, with excellent information, and the thread drifted to scanning to such a point that it is moved to DPUG.
Let us then say I come on as a new member, interested in developing C-41 as B&W, and not interested in scanning. I would likely not find the information.
I might create a new thread asking about this process, and we know how forums everywhere appreciate new threads on the same old subjects
Perhaps someone may then refer me to DPUG - and if I do find the information useful, I will have learned that I may indeed need to search
everything just to find the analog information I seek.
On the other hand, if the thread drifts to scanning, and those posts were relocated to DPUG, leaving the C-41 as B&W parts in APUG, there will likely be some confusion, frustration, and lack of continuity. Off-topic posts that are merely deleted without a trace might also result in ill-will and a lack of confidence. Then again, they may not - I'm just playing Devil's advocate here.
The technical aspects are the easy part. Decisions regarding when to move/delete posts/threads may prove difficult to codify in a consistent manner (this can presently be scene on APUG alone when comparing similar posts in the same sub-fora, where one remains, yet another disappears into oblivion - without even a place-marker like the old system - both having been equally off-topic or "offensive").
Don't get me wrong - I like the idea of being able to switch between or view both APUG and DPUG. It is a noble idea. I've perused DPUG as a non-member, but have found better resources elsewhere.
APUG, however, is yet unequaled.
EDIT: It seems I took too long to compose my post, as Ian just covered much of the same material.