1. A system comprising: one or more modules comprising one or more hardware processors and configured to: receive a textual description of an entry representing a collectible item, the entry being requested for creation within a collection of entries representing collectible items at a network-based system, the textual description of the entry representing the collectible item being submitted by a user of the network-based system and received from a client device of the user by a server system within the network-based system, the entry, after creation, corresponding to a listing of the collectible item at the network-based system; generate a structured description of the entry based on the textual description of the entry, the structured description of the entry including a name-value pair derived from the textual description submitted by the user; determine that the entry is absent from the network-based system; and create the entry within the collection by storing the structured description of the entry in a database of the network-based system based on the determining that the entry is absent from the network-based system.