This free browser extension tool allows you to select text to annotate, which you can then share with others. In addition, you can annotate in groups, search for other annotations online and even comment on each other’s notes! Hypothesis is a new effort to implement an old idea: A conversation layer over the entire web that works everywhere, without needing implementation by any underlying site. Our team creates open source software, pushes for standards, and fosters community. Using annotation, we enable sentence-level note taking or critique on top of classroom reading, news, blogs, scientific articles, books, terms of service, ballot initiatives, legislation and more. Everything we build is guided by our principles. In particular that it be free, open, neutral, and lasting to name a few.