Connie,
Go to the "my profile" tab, scroll down - on the left-hand side of the screen you'll see a "status" tab under your avatar; click on that and you can type in a message. Under that is a "mood" tab, click on the down arrow and select a smiley face mood icon.
When you post to a thread you will always see the "edit" (pencil) icon beside your status and mood choices; apparently this does not appear on your subsequent posts to anyone but yourself, so ignore them!
Thanks to Adam I figured out how this whole thing works - neat concept, as you can change your "mood" as you see fit.
Enjoy!
Emily