An item segment is a group of items that can be made visible to one or more customer segments. PCV supports the following item segments:
Item Collections - you can add specific items to an item collection record either manually or by using a mass update. For more information, see Item Collections.
Commerce Categories - these enable you to create a hierarchical structure of product categories, subcategories, and products for display on your website. If you use commerce categories to organize and display products on your website, you can also use them in PCV to display specific commerce categories to selected customer segments. For more information, see Commerce Categories.
Commerce categories are not always a good fit for PCV because they are not necessarily tailored to individual customers or customer segments. For example, if you have a clothing website, you may want your website visitors to see products organized into Men’s, Women’s, and Accessories categories. But you may want VIP customers to view a “VIP Items” item segment, which contains products from all three categories. In this scenario, where the hierarchical item groupings are distinct from the customer-focused item groupings, it would be much better to create “VIP Items” as an item collection.
Whether you use item collections, commerce categories, or a combination of the two while setting up a personalized catalog view, depends on the result you want to achieve.