When you enable ratings on a list, two site columns are added to the list: number of ratings and rating count. You can also separately add rating columns to lists, or content types for global inheritance. Use the following steps to enable ratings on a single list (or library):
1. Access the list’s Settings page.
2. On the Settings page, under General Settings, click Rating Settings.
3. On the Rating Settings page, under Rating Settings, check the Yes radio button under Allow Items in This List to Be Rated?, as shown in Figure 5.107. Click OK.
Back on the list’s Settings ...