Techniques are disclosed for automatically annotating a document to offer, to a viewer, a choice of operations that a user can take relative to identified entities to which the document refers, where the choice of operations offered in relation to each such entity is appropriate to and based on the types of that entity. In one embodiment of the invention, for each “interesting” entity within a document, a mechanism automatically determines one or more types for that entity. The mechanism automatically annotates the document so that an application will present entity-type-specific data (including operation choices) that is generated by modules that are mapped to the types of the entities within the document. The annotations comprise metadata that indicates types of each “interesting” entity. The entity-type-specific data may be presented along with the rest of the document. A user need not navigate to a different document prior to viewing the data.