1. A method for measuring quality of web objects, the method comprising the computer-implemented steps of: storing behavior data based on how users interact with a search engine; generating one or more graphs that include nodes that represent web objects; wherein at least some edges within said one or more graphs represent implicit links derived from said behavior data; and for each web object in a set of web objects that are represented by nodes in said one or more graphs, generating a quality measure for the web object based on edges within said graph that lead to the node that represents the web object.