13. A system for use in ranking documents, the system comprising: one or more processing devices; and one or more storage devices that store instructions which, when executed, cause the one or more processing devices to implement: a content server configured to enable a user to select documents for viewing from a set of documents; a profile associated with the user configured to maintain information specifying documents selected by the user for viewing within a predetermined time period; at least one positive word vector generated using words contained in at least a segment of at least one of the documents stored in the profile; at least one negative word vector generated using words contained in at least a segment of at least one of the documents that was not selected by the user for viewing; document word vectors generated for a group of documents to be ranked; 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; and rank the group of documents based on the performed vector space relationship analysis; and a classifier configured to classify the documents selected by the user for viewing in predetermined categories; wherein the ranking engine is further configured to rank, based on the ranked group of documents, the predetermined categories; and wherein the profile is further configured to store the ranked categories.
13. A system for use in ranking documents, the system comprising: one or more processing devices; and one or more storage devices that store instructions which, when executed, cause the one or more processing devices to implement: a content server configured to enable a user to select documents for viewing from a set of documents; a profile associated with the user configured to maintain information specifying documents selected by the user for viewing within a predetermined time period; at least one positive word vector generated using words contained in at least a segment of at least one of the documents stored in the profile; at least one negative word vector generated using words contained in at least a segment of at least one of the documents that was not selected by the user for viewing; document word vectors generated for a group of documents to be ranked; 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; and rank the group of documents based on the performed vector space relationship analysis; and a classifier configured to classify the documents selected by the user for viewing in predetermined categories; wherein the ranking engine is further configured to rank, based on the ranked group of documents, the predetermined categories; and wherein the profile is further configured to store the ranked categories. 14. The system of claim 13 , wherein the instructions further cause the one or more processing devices to: store information specifying the documents selected by the user for viewing in the profile; and delete, from the profile, information specifying the documents selected by the user for viewing prior to the predetermined time period.