There is a new feature in SharePoint 2010 called "Ratings" which means you can rate any item (Audio, video image..etc.) in a library. this feature comes activated in "Team Site" but for a Publishing site, you need to manully enable this feature. The feature does not show up in the list, it is a hidden feature. You need to enable it from Power Shell (SharePoint 4.0 Mangement Console). Here is how you turn it on for a publishing site:
enable - spfeatureid - "915c240e-a6cc-49b8-8b2c-0bff8b553ed3" - url "".
Then in order to rate an item in the library, go to the library settings and click Ratings Settings. in "Allow items in this list to be rated" select yes.
enable - spfeatureid - "915c240e-a6cc-49b8-8b2c-0bff8b553ed3" - url "
Then in order to rate an item in the library, go to the library settings and click Ratings Settings. in "Allow items in this list to be rated" select yes.