How to markup
For how to markup annotations in general, see the individual how to markup sections for what you are looking to markup:
- marginalia how to
- reply/comment how to
- bookmark how to
- like how to
- repost how to
- quotation how to
See responses for more types of annotations and details therein.
- See: annotation-use-cases
Opinions about "annotation" (the process/action).
Just a means to an end
To me, annotation is just a means to an end, so talking about promoting annotation is mistaken. Promote the end *via* annotation. #force2016--William Gunn
- News Genius (AKA Genius, RapGenius)
- Amazon allows the sharing of notes and highlights from it's Kindle platform online. Example: recent activity
- On 2016-08-10 Goodreads enabled the ability to sync one's account with their Amazon Kindle account to port over highlights and annotations from Kindle books to the GoodReads platform and share them with one's followers. (GoodReads is a subsidiary of Amazon). The blog post Share Your Kindle Notes and Highlights with Your Friends (Beta) describes the details of the functionality whose UI is pictured below.
- Some of the functionality offered includes
- Highlights and notes are private by default
- A slider on/off button to make individual annotations visible as well as one to make all annotations visible
- The ability to delete individual annotations
- The ability to add notes to each highlight online
- The ability to mark highlights and notes as spoilers.
Other Annotation Related Projects
In 2016/2017 Hypothesis was maintaining an active spreadsheet of sites and services that enabled annotation on the internet.
- Resources in Mirador and from Third Parties
- Annotations at Harvard
- CommentPress Core a WordPress plugin that "allows readers to comment in the margins of a text. Readers may comment paragraph-by-paragraph, line-by-line, block-by-block or by selecting text." (Github)
- The Annotated Grateful Dead Lyrics the web's oldest annotation project?
- YouTube had allowed annotations until 2019-01-15 
On 2017-02-23 the W3C published several inter-related recommendations based on the notes of the Web Annotation Working Group. For some discussion on them, see Annotation is now a web standard post on Hypothes.is blog.
Despite being published as W3C Recommendations, there has been very little actual support in the wild for these W3C specifications, outside of Hypothes.is, which has essentially become a dominant silo for W3C-spec annotations.
Annotation Sites Enable Abuse
Many web-based annotation programs/applications only allow the communities or subgroups who are aware that they exist to see the annotations, thereby making them available for potential abuse.
- 2016-03-25 : How News Genius Silences Writers (archived)
- 2017-04-26 : Un-Annotated (archived)
- 2017-06-24 : More Thoughts on Annotations (archived)
- 2017-06-27 : Thoughts on Audrey Watters’ “Thoughts on Annotation” (archived)
Webmentions could be used to help remedy this potential problem:
- Chris Aldrich has been experimenting since 2018-06-22 with PESOS of highlights and annotations using Hypothes.is to his own website for use as part of his commonplace book. Using Post Kinds Plugin he has created some custom post types for being able to post highlights and annotations as specific post types to his website.
- Examples of highlights can be found here: https://boffosocko.com/kind/highlight/
- Examples of annotations can be found here: https://boffosocko.com/kind/annotation/
- After some initial experimentation, he's considering concatenating the two different types (highlights and annotations) into just one catch-all (annotations). He's also been considering using a yellow "highlighter color" in his UI to mirror the physical world incarnation of ubiquitous pen-like ink highlighters as is sometimes done in fragmention implementations.
- Sometimes he prefers to create read posts under which he includes the highlights and marginalia from the material he's read. (example)
- In all cases, he includes URLs when available and sends webmentions to the original pieces so that they might add in line marginalia as commentary if they prefer.
- Perhaps in the future he'll extrapolate this work using a POSSE workflow?
- He's used ideas and markup from quote posts to guide some of his thinking as well.
- William Ian O'Byrne has been doing some UI experimentation with annotations: Three examples of annotations, bookmarking, & sharing in my digital commonplace book
- Jeremy Cherfas distinguishes between annotations, which are notes created by a reader for their own use, now and in the future, and other kinds of response, which may be directed more at the author of a piece or other readers of that piece. He is old-fashioned about using annotations to build and make sense of his own knowledge archive. These annotations may eventually find their way into published pieces, but in essence are private responses to the piece in question and its relationship to other pieces.
- W3C Web Annotation WG (Previously: W3C Open Annotation Community Group)
- Exploring the UX of web-annotations by Tom Crichlow