In the age of limiting one's digital footprints, I'm wondering if other admins prune users who haven't posted in years so their registration detail isn't sitting on their servers.

I don't seem to find "best practices" regarding this anywhere while searching the web.

Also, I was wondering if it's possible to auto prune users information for those that have, let's say not posted for a certain amount of time/years?

A forum we manage that runs on vBullitin has an automated option to move/prune users based on inactivity, etc. If I were to do it for our UBB Threads run forums, I'd have to do an advanced search and delete by, let's say" last post older than" option. This will leave their posts and replies intact, but submitted by Annonymous, which is fine as I don't want to lose any posts.