1. A system comprising: a commerce database storing item data for a plurality of items offered for sale; a search criteria database storing search criteria associated with a user, the search criteria including search frequency information indicating frequency of a search update to be performed using the search criteria; a search server to retrieve the search criteria from the search criteria database and to perform an update search of the commerce database, the search being performed using the search criteria and in accordance with the search frequency information; and a notification engine to identify an update to a previous search result based on the update search and to generate a notification of the update to the previous search result.