Pruning questions

Hi guys Im afraid I have another question.

Regarding pruning, Ive been looking at the auto pruning now Ive noticed that when I go into a certain forum it shows a section for auto pruning, now if I set that up will it only auto prune that paticular forum or will it auto prune all of my forums/sections. Also if posts/threads are auto pruned and I go in and delete some of them from the basket will my members lose some of there post/thread count, ie if they haves wrote 5 times and one of them or deleted will there count go down to 4.

Thanks for the support Ive received on here already.
Daryn