Patent US 5,960,407

A system for estimating price characteristics of a product from classified advertisements comprising a plurality of textual characters, comprises a relevant classified advertisement database, an attribute filter, a filtered classified advertisement database, a price analyzer and a graphing module. The relevant classified advertisement database stores relevant classified advertisement signals indicative of a subset of the classified advertisements which are directed to the product. The attribute filter receives the relevant classified advertisement signals, and generates in dependence thereupon numeric value signals indicative of prescribed subsets of characters in the subset of the classified advertisements. Each prescribed subset of characters represents a numeric value. The filtered classified advertisement database receives the numeric value signals and stores the numeric value signals. The price analyzer receives the numeric value signals from the filtered classified advertisement database, and determines the price characteristics of the product in dependence on the numeric value signals. The price analyzer also generates price characteristic signals in accordance with the price characteristics of the product. The graphing module receives the price characteristic signals and generates graphical display signals which present the price characteristics of the product in graphic form.