14. The method of claim 13 , where the list of named entities includes location names or consumer products.
13. A method performed by a computer system, the method comprising: receiving, from a client device, a request for a first document from a user, the receiving being performed using a communication interface associated with the computer system; identifying, using one or more processors associated with the computer system, a word or phrase in the first document based on a number of times the word or phrase occurs in the first document and a frequency with which the word or phrase occurs in a language of the first document, locating, using one or more processors associated with the computer system, at least one second document that is relevant to the first document, where the relevance of the second document to the first document is based on the identified word or phrase and based on personal information of the user of the first document, the personal information including at least one of: a geographic location of the user, information provided by the user when registering an account, or information based on a browsing history of the user; embedding, using one or more processors associated with the computer system, a link to the second document within the first document at a location in the first document at which the second document has relevance to obtain a modified version of the first document; and transmitting, using a communication interface associated with the computer system, the modified version of the first document to the client device.