Computer-implemented methods and systems for retrieving potential real estate leads such as expired MLS listings, for-sale-by-owner properties, and foreclosures are described. Expired listings and/or the other leads may be automatically updated, by scanning several electronic sources to discover owner information and when a property is sold or listed/re-listed with a real estate agent. Missing data from the listings may be identified and completed where possible. Moreover, the systems and methods search for and supplement the leads with supplemental information such as property tax data, population demographics, recent comparable sales in the area, et cetera.