1. A method for mapping input listings to consolidated listings, the method comprising computer-implemented steps of: receiving a plurality of input listings from one or more sources, wherein the plurality of input listings comprise different item listing variants for a particular product; establishing from the plurality of input listings, a group of input listings that share one or more common attribute values representing the particular product; determining, for the group of input listings, a single corresponding consolidated listing based on attribute values associated with input listings in the group and attribute values associated with the consolidated listings, wherein the determined single corresponding consolidated listing represents the particular product, wherein the determining, for the group of input listings, the single corresponding consolidated listing comprises: determining whether there is any input listing in the group of input listings that is currently mapped to any consolidated listing, and creating a new consolidated listing and mapping input listings in the group of input listings to the new consolidated listing if there are no input listings in the group of input listings that are mapped to any consolidated listing, wherein the step of the creating the new consolidated listing comprises steps of: assigning a source weight to each source from which any of the plurality of input listings is obtained; calculating sum of source weights for the group; and selecting an item listing from one of the sources to be used as the new consolidated listing for the group if the sum of the source weights is greater than a pre-selected numeric threshold; mapping each input listing in the group of input listings to the determined single corresponding consolidated listing; providing to a user the single corresponding consolidated listing rather than different item listings variants representing the particular product; and at a computer, storing said each mapped input listing in a memory.