1. A computer-implemented method of automatically synthesizing product information from multiple data sources into an on-line catalog, comprising, as implemented on a computer: obtaining historical information corresponding to an existing product represented in the on-line catalog from a plurality of historical data sources, the historical information comprising a plurality of historical attribute-value pairs, and each historical attribute-value pair comprising a historical attribute name and a corresponding historical attribute value, wherein obtaining the incoming and the historical information from the plurality of incoming and historical data sources comprises obtaining unstructured data and structured data in a plurality of different schemas from the plurality of incoming and historical data sources; determining a source-to-catalog attribute correspondence between a first historical attribute name included in a first historical product schema of a first historical data source and a first catalog attribute name of the existing product included in a catalog schema of the on-line catalog, the catalog schema comprising a plurality of catalog attribute-value pairs, and each catalog attribute-value pair comprising a different catalog attribute name and a corresponding catalog attribute value, wherein the first historical attribute name and the first catalog attribute name are not the same name; determining an association between the first catalog attribute name and at least part of a first historical attribute value corresponding to the first historical attribute name of the first historical data source, and storing the existing association between the first catalog attribute name and the at least part of the first historical attribute value corresponding to the first historical attribute name of the first historical data source in the catalog schema; obtaining incoming information corresponding to at least one of the existing product or new product from a plurality of incoming data sources, the plurality of historical data sources or at least one new data source, the incoming information comprising a plurality of incoming attribute-value pairs, and each incoming attribute-value pair comprising an incoming attribute name and a corresponding incoming attribute value; determining a source-to-source attribute correspondence comprising determining a correspondence between a first incoming attribute name included in a first incoming product schema of a first incoming data source and a second incoming attribute name included in a second incoming product schema of a second incoming data source; clustering, based on the source-to-source attribute correspondence, incoming attribute-value pairs so that each cluster corresponds to a different product; extracting attribute-value pairs from the incoming information, comprising; obtaining a particular incoming attribute value corresponding to a particular cluster corresponding to a particular existing product or a particular new product of the on-line catalog; determining based on the learned attribute-value pair extraction, a new association between the particular incoming attribute value and one of: a particular existing catalog attribute name or a particular new catalog attribute name; and adding the new association to the catalog schema; fusing the incoming information, comprising determining, from the new association and at least one other association included in the catalog schema, a representative catalog attribute value corresponding to the one of the existing or the particular new catalog attribute name; and updating, with the representative catalog attribute value, an entry in the on-line catalog corresponding to the particular existing or the particular new product.
1. A computer-implemented method of automatically synthesizing product information from multiple data sources into an on-line catalog, comprising, as implemented on a computer: obtaining historical information corresponding to an existing product represented in the on-line catalog from a plurality of historical data sources, the historical information comprising a plurality of historical attribute-value pairs, and each historical attribute-value pair comprising a historical attribute name and a corresponding historical attribute value, wherein obtaining the incoming and the historical information from the plurality of incoming and historical data sources comprises obtaining unstructured data and structured data in a plurality of different schemas from the plurality of incoming and historical data sources; determining a source-to-catalog attribute correspondence between a first historical attribute name included in a first historical product schema of a first historical data source and a first catalog attribute name of the existing product included in a catalog schema of the on-line catalog, the catalog schema comprising a plurality of catalog attribute-value pairs, and each catalog attribute-value pair comprising a different catalog attribute name and a corresponding catalog attribute value, wherein the first historical attribute name and the first catalog attribute name are not the same name; determining an association between the first catalog attribute name and at least part of a first historical attribute value corresponding to the first historical attribute name of the first historical data source, and storing the existing association between the first catalog attribute name and the at least part of the first historical attribute value corresponding to the first historical attribute name of the first historical data source in the catalog schema; obtaining incoming information corresponding to at least one of the existing product or new product from a plurality of incoming data sources, the plurality of historical data sources or at least one new data source, the incoming information comprising a plurality of incoming attribute-value pairs, and each incoming attribute-value pair comprising an incoming attribute name and a corresponding incoming attribute value; determining a source-to-source attribute correspondence comprising determining a correspondence between a first incoming attribute name included in a first incoming product schema of a first incoming data source and a second incoming attribute name included in a second incoming product schema of a second incoming data source; clustering, based on the source-to-source attribute correspondence, incoming attribute-value pairs so that each cluster corresponds to a different product; extracting attribute-value pairs from the incoming information, comprising; obtaining a particular incoming attribute value corresponding to a particular cluster corresponding to a particular existing product or a particular new product of the on-line catalog; determining based on the learned attribute-value pair extraction, a new association between the particular incoming attribute value and one of: a particular existing catalog attribute name or a particular new catalog attribute name; and adding the new association to the catalog schema; fusing the incoming information, comprising determining, from the new association and at least one other association included in the catalog schema, a representative catalog attribute value corresponding to the one of the existing or the particular new catalog attribute name; and updating, with the representative catalog attribute value, an entry in the on-line catalog corresponding to the particular existing or the particular new product. 9. The method of claim 1 , further comprising obtaining updated incoming information from at least one of the plurality of incoming data sources at least twice daily, and obtaining updated incoming information from all of the plurality of data sources at least monthly.