8. A system for dynamically associating chat sessions with nodes of a browse hierarchy, comprising: a processor; a memory device including instructions that, when executed by the processor, cause the processor to: maintain a dimensional model of a group of documents, the dimensional model reflecting values for a plurality of differentiated attributes for each of the documents of the group of documents, the model comprising a fact table and two or more dimension tables, the fact table comprising multiple rows each containing a document reference that references, for each attribute for which an attribute value was extracted from the document, a row corresponding to the attribute value in a dimension table of the dimensional model corresponding to the attribute; receive a query specifying query attribute values for one or more of the plurality of attributes; and process the query against the dimensional model to generate a query result containing a list of documents in the group of documents having the query attribute values specified by the query.
8. A system for dynamically associating chat sessions with nodes of a browse hierarchy, comprising: a processor; a memory device including instructions that, when executed by the processor, cause the processor to: maintain a dimensional model of a group of documents, the dimensional model reflecting values for a plurality of differentiated attributes for each of the documents of the group of documents, the model comprising a fact table and two or more dimension tables, the fact table comprising multiple rows each containing a document reference that references, for each attribute for which an attribute value was extracted from the document, a row corresponding to the attribute value in a dimension table of the dimensional model corresponding to the attribute; receive a query specifying query attribute values for one or more of the plurality of attributes; and process the query against the dimensional model to generate a query result containing a list of documents in the group of documents having the query attribute values specified by the query. 11. The system of claim 8 , wherein the documents of the group of documents are webpages.