A method for performing a search, which may offer enhanced functionality in particular cases such as identifying similar or partial duplicates of a documents or identifying documents in a document cluster. The method may include accessing a hierarchical network representation of the document, assigning impact values to elements in the network, sequentially performing an activation step for each of the elements in the network starting at the lowest tier, transferring activation status up the network as elements are activated, and generating similarity rankings based on similarity scores.