After some time to think about it, I am setting my journal to the "Adult Concepts" rating as I do have a tendency to get saucy. Most of my stuff is f-locked anyway. (There were over 3,000 posts; I wasn't about to go through them to tag individually.)
My fanfic journal, however, has each post flagged individually based on the content rating for each story so it wasn't a laborious task since I tag with a rating for each fic - and I got to chat with
pheebs1 while I did it.
I have made some suggestions to the LJ Staff about additional functionality for comms, particularly given those that are moderated...but that's another thing.
Just wanted to give folks the heads-up. I'm pretty sure the f-list is all over the age of 18 and this is a moot point. ;-P
EDIT: And because this is me, the comments meandered to some of my speculation about SPN... No spoilers but, you know, just thought I'd warn ya. ;-P