18. A computer readable storage medium having stored therein instructions, which when executed by a computer system having a display, cause the computer system to: receive a first user request including a first set of search keywords; identify a first set of chunks within multiple documents, wherein each chunk includes terms matching the first set of search keywords; display at least a portion of the first set of chunks on the display, including highlighting the terms matching the first set of search keywords in the displayed portion in a first manner; receive a second user request to search among the documents for documents that satisfy a second set of search keywords; identify a second set of chunks within the documents, wherein each chunk includes terms matching the second set of search keywords; and display at least a portion of the second set of chunks on the display, including highlighting the terms matching the second set of search keywords in the displayed portion in a second manner that is different from the first manner.
18. A computer readable storage medium having stored therein instructions, which when executed by a computer system having a display, cause the computer system to: receive a first user request including a first set of search keywords; identify a first set of chunks within multiple documents, wherein each chunk includes terms matching the first set of search keywords; display at least a portion of the first set of chunks on the display, including highlighting the terms matching the first set of search keywords in the displayed portion in a first manner; receive a second user request to search among the documents for documents that satisfy a second set of search keywords; identify a second set of chunks within the documents, wherein each chunk includes terms matching the second set of search keywords; and display at least a portion of the second set of chunks on the display, including highlighting the terms matching the second set of search keywords in the displayed portion in a second manner that is different from the first manner. 23. The computer readable storage medium of claim 18 , wherein the second set of chunks includes at least one chunk that is not included in the first set of chunks.