The present invention provides a system for and a method of collaborative annotation of digital content. In accordance with an embodiment of the present invention, a method of annotating digital content is provided. An annotation related to a portion of a volume of digital content is created. The annotation is stored in computer-readable memory in a manner that maintains a logical connection between the annotation and the portion of the volume of the digital content. The annotation is created by a first user. A comment is created by a second user in response to the annotation. The comment is stored in computer-readable memory in a manner that maintains a logical connection between the comment and the annotation. The portion of the volume of the digital content is displayed together with at least an identification of the annotation and at least an identification of the comment.