A user provides an annotation, such as text or graphics, in relation to a resource available on a computer network. The annotation is automatically stored and/or retrieved without requiring separate action from the user to accomplish the storage or retrieval. An annotation interface may receive the annotation from the user. The annotation is then stored in association with the user and the network address of the resource. The user's annotation may be later retrieved and displayed to the user based on the network address of the resource. In one specific embodiment, a browser toolbar receives and displays user annotations associated with Web sites or Web pages to which the user has navigated. Preferably, the annotation interface remains available to the user throughout the time in which the resource is provided. Further controls may enable the user to make an annotation publicly available to others, and to receive annotations from others.