1. A method comprising: classifying a document as a first class if the document is accessible to a classification agent, and classifying the document as a second class otherwise; associating content of the document according to the document classification; subsequent to the classifying, monitoring network traffic; determining if at least a portion of content of the monitored network traffic corresponds to a portion of the document content, and if so, then classifying a portion of the monitored network traffic according to the classification of the corresponding portion of the document content; and performing a first action if the portion of the monitored network traffic is classified as the first class, and performing a second action otherwise.