You can use the Content rating features to allow live site users to rate any page on your website. For example, you can let users express their opinion about the quality of content. The Content rating features has no dedicated user interface. The overall rating of each page is available in the Rating field while editing the given page in the Pages application on the Properties -> General tab.
One way of enabling the content rating functionality is placing the Content rating web part on a page. See Using the Content rating web part.
You can also include a rating control in transformations to enable users to rate each transformed item. See Displaying content rating in transformations.
Besides, the content rating functionality is integrated in web parts belonging to the Message boards application. This enables live site users to submit a rating along with a comment posted to the message board. See Using content rating in message boards.