Just something I thought of because cats (other art board lmod) and I often ninja each other in moderations, and we don't know if one person sent a pm to another person. If a thread is being viewed by a moderator, I think a message on the title of the thread should pop up saying it is being viewed by a moderator.

This prevents, like I said, ninja'ing of posts and double moderation PMs, which I'm sure people find more of a hassle than help.

Wether or not this information should be shared publicly, I don't know. But having this feature implemented would be of help to many active mods in their boards.