The Classifieds (Listings) view is where your users can post their own listings. What type of listings (buy-and-sell, shift swap requests, etc) is up to you and your organization. You can learn more about the customization options here.
To enable or rename Classifieds (Listings)
1. Go to Administration Settings > Views and Functions > Manage Views and Options and scroll down to Listings.
2. To enable this view check the "Enabled" button..
3. To rename the view something more appropriate for your organization, go to View name and enter your custom name where indicated. You can also customize the names of the items that will be posted in this view.
4. Scroll down and click the blue Save button.
Once Classifieds (Listings) is enabled, all users will be able to access it from the Main Navigation.
NOTE—there are two Administrator roles to assign for Classifieds, Creators and Managers
To learn more about Classified ads, refer to this article