I think it's likely easy to deal with right now...

First do an Admin Zone search for Guest.

It should show various language strings. Most of them come though one called GUEST I think, but there'll probably be some others that reference it within wider sentences.

Thank you, I finally realized that I needed to change the 'By_simple' string

Oops, that one doesn't work because then every poster got re-labeled to the new name. I'm still looking

forgot to mention that I did try changing just the 'Guest' string, but I didn't see any change, and it's not in the list of language strings that are pulled up when looking at a forum page with an anonymous post

It should mainly be the GUEST language string (which is in the 'global' language file). Change that to "Anonymous Member".

That is what would be combined with BY_SIMPLE, to make the message you're seeing.

I will definitely take a look for you, but it might be a couple of hours as I'm in the middle of rearranging some notes.

Aahah! The system isn't showing the 'Guest' language string change on an existing post (even if I empty all related caches). It only shows 'Anonymous Member' if I make a new forum post

I just posted a quick tutorial to:
http://compo.sr/site/s/1/15.htm

Thank you Chris for the tutorial and OCLE command. I want to keep the 'guest' usergroup name as it is so that it's distinguished from logged-in members who post anonymously. Therefore I've only applied the OCLE command, and we're in business. Thanks