I believe that it's supposed to be a quill... What they used to write with before pens. A feather with the tip cut off that one would dip into an inkwell and then use to write with. I think... I could be wrong though...
I'm assuming you're talking about the icon next to each subforum on the main page. Yellow means there are no unread posts in that particular subforum, and red means there are new, or unread, posts.
They already answered it, but indeed, it's a quill, as is the "F" in our WritingForums logo. Can't you tell?
