Yes, it is possible to build reviews/star ratings functionality per CMS item without it being an eCommerce product. Here's a detailed explanation of how you can achieve this:

1. Choose a CMS: Select a CMS (Content Management System) that supports custom fields and plugins/extensions to add the review functionality. Some popular CMS options include WordPress, Drupal, and Joomla.

2. Install a Reviews Plugin/Extension: Look for a reviews plugin or extension that integrates with your chosen CMS. These plugins/extensions provide the necessary tools to add review functionality to your CMS items. Here are a few examples:

   • WordPress: You can use plugins like WP Product Review, WP Customer Reviews, or WP Review.
   • Drupal: Modules like Fivestar, Rate, or Voting API can be used to add review functionality.
   • Joomla: Extensions such as JLex Review, JReview, or JComments can be used.

3. Configure the Plugin/Extension: Once installed, configure the plugin/extension according to your requirements. This includes setting up the rating system, review submission form, and any additional customization options the plugin/extension provides.

4. Create a Custom Field: If the chosen plugin/extension doesn't provide a built-in way to associate reviews with specific CMS items, you may need to create a custom field for each product/item. This field will store the review data and link it to the respective item. Most CMSs allow you to create custom fields easily.

5. Display Reviews on CMS Item Pages: Edit the CMS item template or page where you want to display the reviews. Use the plugin/extension functions or shortcodes to fetch and display the reviews associated with that specific item. You can customize the display format using CSS to match your desired design.

6. Allow Users to Submit Reviews: Enable the review submission form provided by the plugin/extension on the CMS item pages. Users can then submit their reviews and ratings for the respective products/items. Ensure you have proper moderation and spam prevention measures in place to maintain the quality of reviews.

7. Customize Rating System: If you want to customize the way products/items are rated, you may need to modify the plugin/extension or use additional customization options provided by the plugin/extension. This could involve changing the rating scale, adding custom criteria, or implementing advanced algorithms for calculating overall ratings.

Remember to regularly update the plugins/extensions and keep an eye on any security vulnerabilities or compatibility issues that may arise.

Overall, by leveraging CMS plugins/extensions and custom fields, you can easily add reviews/star ratings functionality to your CMS items, even if you don't sell them online.