An online marketplace system provides various features for assisting users in listing products for sale, locating the listings for a product, and performing related actions. A user wishing to sell a product can browse to an existing description of the product in an electronic catalog and then select an option to create a corresponding listing. If the user previously purchased the product via the system, the user may alternatively select the product from a personal purchase history. The system may also proactively send product-specific listing requests to those predicted to own specific products. To create a listing for a selected product, the user preferably specifies the product's condition and a selling price. The pending listings for a product are preferably displayed or summarized on the product's detail page in the catalog. In one embodiment, the catalog also servers as a retail sales catalog of an online merchant.