A system and method in a computer network in which computer users may make handwritten annotations (to publication pages such as a slideshow slide) public to other computer users, as well as to view public annotations from other computer users. Users can selectively publish authored notes, and subscribe to other user's published notes, as well as see who is subscribing to those notes. An annotation program such as running on a tablet personal computer allows a user to operate in a public mode or a private mode. In the public mode, an author's ink strokes are sent to a server which distributes those ink strokes to subscribers of that author. The architecture provides other useful applications, including a shared canvas mode in which any user annotations corresponding to a publication page are viewable to other users, and a graffiti mode in which annotations are persisted independent of any publication page.