Patent ID: 7137065

Claim:
A method for classifying electronically posted documents, the method comprising: receiving a first document and a second document; generating a first metadata summary for said first document and a second metadata summary for the second document, wherein the first metadata summary includes a first plurality of sub-trees and the second metadata summary includes a second plurality of sub-trees, and wherein each of the sub-trees includes a plurality of nodes; comparing the first and second metadata summaries on a structural level by comparing a structure of the sub-trees of the first metadata summary with a structure of the sub-trees of the second metadata summary; identifying the first and second documents as distinct if the structures of the sub-trees of the first and second metadata summaries are not equivalent; if the structures of the sub-trees of the first and second metadata summaries are equivalent, performing a further comparison of the first and second metadata summaries, wherein the further comparison of the first and second metadata summaries includes the sub-steps of: comparing the first and second metadata summaries on a textual level by comparing textual content from the first document that is contained in the sub-trees of the first metadata summary with textual content from the second document that is contained in the sub-trees of the second metadata summary; and identifying the first and second documents as distinct if the textual content within the sub-trees of the first and second metadata summaries are not equivalent, wherein the method further comprises: defining a first equivalence metadata table comprising: a first row corresponding to the first metadata summary; a second row corresponding to the second metadata summary; a first column corresponding to the first metadata summary; and a second column corresponding to the second metadata summary, and wherein the step of identifying the first and second documents as distinct if the structures of the sub-trees of the first and second metadata summaries are not equivalent comprises storing a zero value in the first row and second column position of the first equivalence metadata table; and wherein the step of identifying the first and second documents as duplicates comprises removing the second metadata summary.