21. A computer-implemented method comprising: receiving a user query; identifying at least first and second documents from a database in response to the user query, with the first and second documents associated with respective first and second feature vectors, each feature vector having a plurality of equal-length binary representations of terms or features within its respective document, with the terms or features selected based on relative magnitude of corresponding inverse-document-frequency (idf) values within a table of inverse-document-frequency values; determining whether temporal traits of the first and second documents are within a first range of each other; determining whether length traits of the first and second documents are within a second range of each other; and in response to identifying the first and second documents and at least one determination being affirmative, comparing the first and second feature vectors.
21. A computer-implemented method comprising: receiving a user query; identifying at least first and second documents from a database in response to the user query, with the first and second documents associated with respective first and second feature vectors, each feature vector having a plurality of equal-length binary representations of terms or features within its respective document, with the terms or features selected based on relative magnitude of corresponding inverse-document-frequency (idf) values within a table of inverse-document-frequency values; determining whether temporal traits of the first and second documents are within a first range of each other; determining whether length traits of the first and second documents are within a second range of each other; and in response to identifying the first and second documents and at least one determination being affirmative, comparing the first and second feature vectors. 24. The method of claim 21 , wherein presenting search results identifying at least one of the first and second documents comprises presenting a listing of a title of the first document and wherein the indication of whether the first and second documents contain content that is duplicative of each other, includes: presenting a listing of a title of the second document that is below and indented relative to the title of the first document; or presenting a listing of a title of the second document in a font that differs from that of the title of the first document; or presenting a folder or other container icon which is selectable to display a listing of one or more documents that identifies the second document.