1. A method of detecting web pages belonging to at least one similarity class from a plurality of web pages, the method comprising: determining clusters of the plurality of web pages based on characteristics of the content of the web pages; determining, for each of the determined clusters, at least one metric indicative of similarity among resource locators associated with the web pages of that cluster; and determining the web pages belonging to the at least one similarity class based on the determined clusters and the determined similarity metrics.