This is a Store catalog page for Classifieds type of products. You can add/disable widgets in this page, categories and display classfieds items in Grid, Mini View, List View and Table.
To allow users to post items, you will need jMarket to bolt-on with jClassifieds to handle the multi-vendor functionality.
Note: Classifieds items are items that you cannot checkout and pay. You simply use it to post ads like Olx or craigslist.