1. A computer implemented method, comprising: at a server system having one or more processors and memory storing one or more programs executed by the one or more processors, in a document editor application executed by the server system: receiving from a respective client system a subset of an existing document, wherein the subset is identified in accordance with a user action within the existing document and displayed at the respective client system; in response to receiving from the respective client system the subset of the existing document: identifying a most recently edited portion of the document, and a remainder portion of the subset of the document that excludes the most recently edited portion; identifying one or more key words in the received subset of the document as query terms of a search query, wherein the received subset of the document includes additional terms distinct from the identified one or more key words, and wherein: the one or more key words in the received subset of the document correspond to a difference set of words, the difference set of words comprises words included in a first set of words other than words included in a second set of words, the first set of words includes high ranking words among words in a most recently edited paragraph, in the most recently edited portion, ranked in accordance with inverse document frequency values, and the second set of words includes high ranking words among words in the remainder portion of the document ranked in accordance with inverse document frequency values; identifying one or more information items, including initiating a search by sending the search query to a search engine system distinct from the server system, the search query having the one or more key words identified in the subset of the document as the query terms of the search query; and sending to the respective client system, for display at the respective client system, a focus region of each of the one or more identified information items, each focus region comprising a region of a respective identified information item corresponding to at least one of the one or more key words; receiving a selection of an information item in the one or more identified information items, the selection by a user associated with the respective client system; and in response to receiving the selection of the information item, modifying the document by inserting a citation to the selected information item.
1. A computer implemented method, comprising: at a server system having one or more processors and memory storing one or more programs executed by the one or more processors, in a document editor application executed by the server system: receiving from a respective client system a subset of an existing document, wherein the subset is identified in accordance with a user action within the existing document and displayed at the respective client system; in response to receiving from the respective client system the subset of the existing document: identifying a most recently edited portion of the document, and a remainder portion of the subset of the document that excludes the most recently edited portion; identifying one or more key words in the received subset of the document as query terms of a search query, wherein the received subset of the document includes additional terms distinct from the identified one or more key words, and wherein: the one or more key words in the received subset of the document correspond to a difference set of words, the difference set of words comprises words included in a first set of words other than words included in a second set of words, the first set of words includes high ranking words among words in a most recently edited paragraph, in the most recently edited portion, ranked in accordance with inverse document frequency values, and the second set of words includes high ranking words among words in the remainder portion of the document ranked in accordance with inverse document frequency values; identifying one or more information items, including initiating a search by sending the search query to a search engine system distinct from the server system, the search query having the one or more key words identified in the subset of the document as the query terms of the search query; and sending to the respective client system, for display at the respective client system, a focus region of each of the one or more identified information items, each focus region comprising a region of a respective identified information item corresponding to at least one of the one or more key words; receiving a selection of an information item in the one or more identified information items, the selection by a user associated with the respective client system; and in response to receiving the selection of the information item, modifying the document by inserting a citation to the selected information item. 3. The method of claim 1 , wherein the one or more key words in the received subset of the document correspond to high ranking words among words in the document ranked in accordance with inverse document frequency values.