is web-based, free open source software that enables text annotation on the web privately and publicly to facilitate collaboration.
is web-based, free open source software that enables image annotation on the web.
is a web-based video annotation tool for mobile and desktop devices. Use VideoAnt to add annotations, or comments, to web-hosted videos. VideoAnt-annotated videos are called "Ants." You can export your annotations in a variety of data formats and even embed your Ants on a personal website, learning management system, or anywhere HTML is allowed.