US Patent 9760868 Electronic document annotation

Annotating a document in a data processing system, wherein the document includes a first content section and a data structure, can include receiving a request to annotate the document, wherein the request comprises an annotation, and an identification of the document to annotate, and creating a second content section comprising the annotation. The data structure can be updated with a reference to the second content section thereby making the second content section available as an annotation in association with the document.