# What is an Annotation?

Annotations are comments, notes, explanations, or other types of external remarks that can be attached to a Web document or a selected part of the document. As they are external, it is possible to annotate any Web document independently, without needing to edit that document. From the technical point of view, annotations are usually seen as metadata, as they give additional information about an existing piece of data. In this project, we use a special RDF annotation schema for describing annotations.

Annotations can be stored locally or in one or more annotation servers. When a document is browsed, Amaya queries each of these servers, requesting the annotations related to that document. Currently Amaya presents annotations with pencil annotation icons ( )that are visually embedded in the document, as shown in the figure below. If the user single-clicks on an annotation icon, the text that was annotated is highlighted. If the user double-clicks on this icon, the annotation text and other metadata are presented in a separate window.

An annotation has many properties including:

- Physical location: is the annotation stored in a local file system or in an annotation server
- Scope: is the annotation associated to a whole document or just to a fragment of this document
- Annotation type: 'Annotation', 'Comment', 'Query', ...