Same thing I noticed yesterday night. Because, I was looking for such symbol on my page at WC and JoeUser.
Actually I was building the yahoo 360 personal page for me: http://360.yahoo.com/hcp006sl.
To build the feed section a personal site was needed that contains that orange symbol at the corner and I have to mention the link that I shall get from that symbol, i.e., hold the mouse on that symbol your browser will show you a link associated with that symbol. This link was needed for that feed section.
Thus I discovered the symbol. 'RSS' symbol also appears on http://hcp.joeuser.com/. But, it doesn't works. If you click on it, it shows 'The page that you have requested cannot be found'.
So, this is the story of that symbol.
