Hi, nice shot. In answer to your question, everyone has an option to 'rate' a photo when they leave a comment (as I have just done), but some people may just comment without a rating. You don't have to do anything to make this facility available.
Good shot. I'm guessing your name is Aidan? thus answering Chris's question. As far as you not seeing a rating system for your photo - this is because it is your own image. You can only give ratings to other peoples photos and the system therefore doesnt appear against your own shots. Cheers RichardRichard Crowe Visit My Website