Exposing annotations in a document

Abstract

A technique is described herein for effectively exposing annotation information in a document for use by various applications. The technique involves generating a tag tree data structure that identifies a collection of tag elements associated with a document. The technique also generates an overlay data structure that identifies a collection of annotations associated with the document. The overlay data structure also links the annotations to corresponding parts identified in the tag tree data structure. The technique then uses the tag tree data structure and the overlay data structure to provide information to a document-consuming component that conveys an order in which one or more annotations appear in the document relative to one or more parts in the document. According to one illustrative aspect, at least one annotation described by the overlay data structure is an active annotation, corresponding to a transient annotation that has not been saved.