When you are logged in to your account and you search the catalog, you will be able to rate items on a scale of 1 to 5 stars (including half stars). Your rating will appear as a set of blue stars next to the item.
Items you have rated will display your rating next to the item's average rating (gold stars) to the right of the cover image. You may change your rating at any time while logged in to your account by selecting a different number of stars or you can delete you rating by clicking on the red X which appears when you hover over your rating.
You do not have to be signed in to see the average rating other people have given an item.