23. A system for use in personalizing advertising for a user, the system comprising: one or more processing devices; and one or more storage devices storing instructions which, when executed, cause the one or more processing devices to implement: a content server configured to present documents, from a set of documents, to a user such that the user can select documents for viewing; at least one positive word vector formed using words contained in at least a segment of the documents in the set of documents that are selected by the user for viewing; at least one negative word vector formed using words contained in at least a segment of the documents in the set of documents that are not selected by the user for viewing; one or more document word vectors for at least some of the documents that were selected by the user for viewing; a ranking engine configured to: perform a vector space relationship analysis of the positive word vector, the negative word vector, and the document word vectors; establish a document rank order of the documents selected by the user for viewing based on the performed vector space relationship analysis; classify the documents selected by the user for viewing in predetermined categories; and rank the predetermined categories based on the document rank order; and an ad server, operatively coupled with the ranking engine, for presenting, to the user in a selected context, advertisements associated with the ranked categories.
23. A system for use in personalizing advertising for a user, the system comprising: one or more processing devices; and one or more storage devices storing instructions which, when executed, cause the one or more processing devices to implement: a content server configured to present documents, from a set of documents, to a user such that the user can select documents for viewing; at least one positive word vector formed using words contained in at least a segment of the documents in the set of documents that are selected by the user for viewing; at least one negative word vector formed using words contained in at least a segment of the documents in the set of documents that are not selected by the user for viewing; one or more document word vectors for at least some of the documents that were selected by the user for viewing; a ranking engine configured to: perform a vector space relationship analysis of the positive word vector, the negative word vector, and the document word vectors; establish a document rank order of the documents selected by the user for viewing based on the performed vector space relationship analysis; classify the documents selected by the user for viewing in predetermined categories; and rank the predetermined categories based on the document rank order; and an ad server, operatively coupled with the ranking engine, for presenting, to the user in a selected context, advertisements associated with the ranked categories. 29. The system of claim 23 , wherein the ranking engine is configured to perform the vector space relationship analysis by applying Rocchio's method to the positive word vector, the negative word vector, and the document word vectors.