The Web Annotation Data Model specfication describes a structured model and format to enable annotations to be shared and reused across different hardware and software platforms to support a wide variety of simple as well as complex application use cases.

Annotations are typically used to convey information about a resource or associations between resources. Simple examples include a comment or tag on a single web page or image, or a blog post about a news article.

The Web Annotation Protocol describes the transport mechanisms for creating and managing annotations in a method that is consistent with the Web Architecture and REST best practices.

The Web Annotation Vocabulary specifies the set of RDF classes, predicates and named entities that are used by the Web Annotation Data Model. It also lists recommended terms from other ontologies that are used in the model, and provides the JSON-LD Context and profile definitions needed to use the Web Annotation JSON serialization in a Linked Data context.

This document does not define any new approach to selection. Instead, it relies on existing techniques, providing a common model and syntax to express and possibly combine selections. The formal specification and the semantics originate from a separate Recommendation, namely the Web Annotation Data Model, where it is used to select targets of annotations. The current document only “extracts” Selectors and States from that data model; by doing so, it makes their usage easier for applications developers whose concerns are not related to annotations.

This Note describes and illustrates potential approaches for including annotations within HTML documents. Examples also are included illustrating the use within an HTML document of annotation Selectors as fragment identifiers.