Efficient and effective Web change detection

In this paper we present a new technique for detecting changes in Web documents. The technique is based on a new method to measure the similarity of two documents, that represent the actual and the previous version of the monitored page. The technique has been effectively used to discover changes in selected portions of the original document. The proposed technique has been implemented in the C.M.W system providing a change monitoring service on the Web. The main features of C.M.W. are the detection of changes on selected portions of web documents and the possibility to express complex queries on the changed information.