14. A system comprising: means, including a processor and memory, for extracting information from a first input document; means, including a processor and memory, for retrieving one or more second documents based on the extracted information; a learning machine for identifying one or more of the second documents as more probably related to the first input document than one or more of the other second documents; and wherein the learning machine comprises: support-vector processor means, including a processor and memory, for defining a multi-dimensional feature vector for each second document, with the vector having a set of features including a similarity feature indicating similarity of at least a portion of the second document to a portion of the first input document wherein each of the feature vectors is based on a title similarity score for one or more portions of a said second document and a said first input document.
14. A system comprising: means, including a processor and memory, for extracting information from a first input document; means, including a processor and memory, for retrieving one or more second documents based on the extracted information; a learning machine for identifying one or more of the second documents as more probably related to the first input document than one or more of the other second documents; and wherein the learning machine comprises: support-vector processor means, including a processor and memory, for defining a multi-dimensional feature vector for each second document, with the vector having a set of features including a similarity feature indicating similarity of at least a portion of the second document to a portion of the first input document wherein each of the feature vectors is based on a title similarity score for one or more portions of a said second document and a said first input document. 15. The system of claim 14 , wherein the learning machine comprises a support vector machine.