9. A system in a computer system, comprising: a content selection monitor configured to detect a selection mode initiated by a user with regard to a displayed document that includes content, and to automatically detect, while in the initiated selection mode, content selected by a user in the displayed document; an entity determiner configured to automatically determine, in response to the detection of the selection mode initiated by the user, a plurality of entities in the displayed document, each entity of the plurality of entities including a portion of the displayed document content different from the detected selected content; a document annotator configured to automatically annotate the displayed document to indicate each of the determined plurality of entities; and an associated entity determiner configured to automatically determine, in response to said determining the plurality of entities in the displayed document, at least one entity of the plurality of entities that includes content of the displayed document content that is associated with the detected selected content; the document annotator configured to automatically indicate in the displayed document the determined at least one entity as one or more active entities.
9. A system in a computer system, comprising: a content selection monitor configured to detect a selection mode initiated by a user with regard to a displayed document that includes content, and to automatically detect, while in the initiated selection mode, content selected by a user in the displayed document; an entity determiner configured to automatically determine, in response to the detection of the selection mode initiated by the user, a plurality of entities in the displayed document, each entity of the plurality of entities including a portion of the displayed document content different from the detected selected content; a document annotator configured to automatically annotate the displayed document to indicate each of the determined plurality of entities; and an associated entity determiner configured to automatically determine, in response to said determining the plurality of entities in the displayed document, at least one entity of the plurality of entities that includes content of the displayed document content that is associated with the detected selected content; the document annotator configured to automatically indicate in the displayed document the determined at least one entity as one or more active entities. 11. The system of claim 9 , wherein the associated entity determiner is configured to transmit the displayed document and an indication of the detected selected content over a network to a document analysis service, and to receive an indication of the at least one entity from the document analysis service over the network.