A human viewing temporally-dimensioned content of a multimedia document through use of a computer can add substantive content to temporally-dimensioned content of the multimedia document to thereby annotate, comment upon, and augment the multimedia document. Thus, a multimedia document becomes a basis for collaborative work. The substantive content added by the viewing user is in the form of a temporal annotation which identifies a particular relative time in temporally-dimensioned content of the multimedia document and which includes user-authored content provided by the viewing user. Display of the multimedia document includes presentation of the temporal annotations created by the user. A graphical user interface enables the user to select a temporal annotation from a list and immediately proceed to presentation of the multimedia document such that temporally-dimensioned content is presented at the particular relative time represented by the selected temporal annotation. In addition, as temporally-dimensioned content of the multimedia document is displayed, temporal annotations are represented in the display of the multimedia document as the particular relative time represented by each temporal annotation is reached. Thus, the user-authored content becomes part of the display of the multimedia document in a temporal context.