Web-based annotations of digital books enrich a scholarly text through overlays and filters that sit on top of the text in order to show additional commentary and feedback. Annotations-in short, a form of readerly or writerly interaction that consists of notes (in any medium) added to texts (of any medium) 1 -already have a long history in a print and manuscript context (e.g., marginalia, errata, rubrics), but the immediacy of two-way discussion between users is a notable feature of digital open annotations, both of comments at the bottom of a text and in-line text annotations. Bertino and Staines therefore liken annotation to a "conversation" between authors and audiences that was previously much less interactive Bertino & Staines, . In addition to this, for Tara McPherson annotations (of e.g., digital visual archives) may also facilitate a more "seamless integration of research materials and scholarly analysis" through a closer presentation between commentary and the object studied (McPherson, ). This is particularly useful in a scholarly communication environment where annotations enable discussions to take place in direct proximity to the material that is under consideration, for example with linguistic markup of text corpora. Open online annotation fulfils several functions that can be beneficial for scholarly communication. Kalir and Garcia summarise the common purposes of annotation quite succinctly: "to provide information, to share commentary, to spark conversation, to express power, and to aid learning" Kalir & Garcia, . Bertino and Staines mention that in addition to enabling collaborations and the opportunity to engage more directly with authors atop of research materials, open annotation allows feedback from readers, corrections and updates, enables inline (open) peer review, augmentation of publications with additional (multimedia) information, connections to related resources, further context around citations, and it offers opportunities within pedagogical settings. 2 They also point out that, beyond human generated annotations, there are also opportunities to enhance content through auto-generated annotations which, as they state, "might include additional information around identifiers, controlled vocabulary, or recommendations" Bertino & Staines, . In this context they explain that there are also opportunities for various semantic applications where the open annotation of documents allows annotations to be "searchable by tags that make it possible to identify the type of annotation or its content" (Bertino & Staines, , Lange, ). In , the World Wide Web Consortium (W C), the standards body for the web,