What is Hypothesis?

Hypothesis is web-based annotation software that can be used to annotate both html and pdf documents.  Hypothesis enables highlighting  and sentence-level note taking or critique on top of news, blogs, scientific articles, books, terms of service, ballot initiatives, legislation and more.  The tool is available as a browser extension or bookmarklet

To annotate with Hypothesis, you will need to create a free account then install either a Chrome extension or bookmarklet for other browser types.