25. A system, comprising: one or more computer devices configured to: obtain a set of one or more addresses, each address, in the set of one or more addresses, corresponding to a respective first document, and the set of one or more addresses being selected or identified by a user, receive, after obtaining the set of one or more addresses, a search query from the user; obtain a list of links to second documents based on the search query, where each address, in the set of one or more addresses, is obtained independently of the list of links and independently of the search query; filter the list of links, using the set of one or more addresses, to identify a subset of the links in the list of links, where the subset of the links includes fewer than all of the links in the list of links, when filtering the list of links, the one or more computer devices are configured to: determine whether text associated with a body of a second document, corresponding to one of the links in the list of links, corresponds to a same topic as text associated with a body of the respective first document corresponding to an address in the set of one or more addresses, and include, in the subset of the links, the one of the links when the text associated with the body of the second document corresponds to the same topic as the text associated with the body of the respective first document; and provide information regarding the subset of the links to the user.
25. A system, comprising: one or more computer devices configured to: obtain a set of one or more addresses, each address, in the set of one or more addresses, corresponding to a respective first document, and the set of one or more addresses being selected or identified by a user, receive, after obtaining the set of one or more addresses, a search query from the user; obtain a list of links to second documents based on the search query, where each address, in the set of one or more addresses, is obtained independently of the list of links and independently of the search query; filter the list of links, using the set of one or more addresses, to identify a subset of the links in the list of links, where the subset of the links includes fewer than all of the links in the list of links, when filtering the list of links, the one or more computer devices are configured to: determine whether text associated with a body of a second document, corresponding to one of the links in the list of links, corresponds to a same topic as text associated with a body of the respective first document corresponding to an address in the set of one or more addresses, and include, in the subset of the links, the one of the links when the text associated with the body of the second document corresponds to the same topic as the text associated with the body of the respective first document; and provide information regarding the subset of the links to the user. 27. The system of claim 25 , where, when obtaining the set of one or more addresses, the one or more computer devices are configured to include an address, associated with a document accessed by the user, in the set of one or more addresses.