1. A system for matching sources with interest, the system comprising: a computing device comprising a processor, the processor configured to execute computer-readable instructions that configure the processor to at least: obtain a plurality of interest indicators from one or more interest resources, each interest indicator describing an item; generate a set of interest keywords based at least in part on the plurality of interest indicators; identify the item based, at least in part, on the set of interest keywords; submit a search request comprising the set of interest keywords to a network-based information resource, the search request configured to identify item sources that offer the item for sale; obtain, from the network-based information resource, search results comprising one or more item sources offering the item for sale that correspond to the set of interest keywords; for individual item sources of the one or more item sources, determine a score associated with the item source, wherein the score is based, at least in part, on at least one sourcing parameter associated with the item source, wherein the at least one sourcing parameter identifies an estimated number of users employing the item source; identify, from the search results, an item source of the one or more item sources capable of providing the item for sale based, at least in part, on the determined score associated with the item source; determine that the identified item source has the item in stock; and in response to determining that the identified item source has the item in stock, transmit an offer to the identified item source, the offer comprising an invitation to provide the item for sale through a network-based service; and an electronic data store in communication with the computing device, wherein the electronic data store is configured to store interest keywords generated by the computing device.