My $.02: the hardest part of web-scale annotation isn’t the supply of annotation tools, it’s the *demand* for and use of them by researchers— Dan Cohen (@dancohen) December 1, 2015
Traditional annotations are marginalia, errata, and highlights in printed books, maps, picture, and other physical media. Web annotations are an attempt to recreate and extend that functionality as a new layer of interactivity and linking on top of the Web. It will allow anyone to annotate anything anywhere, be it a web page, an ebook, a video, an image, an audio stream, or data in raw or visualized form. Web annotations can be linked, shared between services, tracked back to their origins, searched and discovered, and stored wherever the author wishes; the vision is for a decentralized and open annotation infrastructure.