Annotator is an open source JavaScript library to easily add annotation functionality to any webpage. Annotations can have comments, tags, links, users, and more. Annotator is designed for easy extensibility so it's a cinch to add a new feature or behaviour. Annotator also fosters an active developer community with contributors from four continents, building 3rd party plugins allowing the annotation of PDFs, EPUBs, videos, images, sound, and more. Adding an annotation to any website is easy with Annotator. First, download the Annotator library, and include it in your HTML. Annotator has a simple but powerful plugin architecture. Plug-ins can also be included for adding functionality such as user permissions, tags, filtering, and formatting. More than a dozen projects rely on Annotator for their digital annotation needs and many are open source. Share text and video annotations using social networks or email.