Patent ID: 8886660

Claim:
A method for tracking a change in a collection of web documents, said web documents being provided by a web site, the method comprising: retrieving the web documents of said collection of web documents at a first assigned point in time and at a second assigned point in time that is later than the first assigned point in time; calculating a similarity measure for a combination of a first retrieved web document of the retrieved web documents at the first assigned point in time and a second retrieved web document of the retrieved web documents at the second assigned point in time to determine whether the second retrieved document corresponds with the first retrieved document; if the second retrieved web document corresponds to the first retrieved web document, comparing said calculated similarity measure for said first and second retrieved web documents with an upper similarity threshold for the similarity measure for detecting a substantial change in content of the corresponding first and second retrieved web documents; and identifying pairs of corresponding web documents retrieved at the first assigned point in time and of web documents retrieved at the second assigned point in time, a similarity score value between the corresponding web documents of said pairs exceeding a predetermined lower similarity threshold value and falling below the upper similarity threshold, the upper similarity threshold being a predetermined upper similarity threshold value.