Genius Web Annotator
https://genius.com/web-annotator

Genius lets you add line-by-line annotations to any page on the Internet. Only a handful of people know that the web browser’s big missing feature—the feature that was supposed to be in from the start but didn’t make it—is the ability to annotate any page on the Internet. Since we founded Rap Genius in 2009, we’ve built an amazing community for breaking down the meaning of anything you’re reading line-by-line — whether it’s Yeezus or Shakespeare — but it’s all been confined to our site. Now, with the Genius Web Annotator, it’s possible to add context, commentary, and images directly on top of any web page using only your browser. News Genius is revolutionizing the way people interact with the news. Rather than seeing reporters and news organizations as the gatekeepers to information, we see journalism as an ongoing and evolving discussion between many parties. We’re a community of journalists, news junkies, designers, engineers, students, you name it, annotating new stories every day, along with original texts (like transcripts and speeches). This will be added to World Wide Web Reference Subject Tracer™. This will be added to Student Research Resources Subject Tracer™. This will be added to Education and Academic Resources Subject Tracer™. This will be added to Business Intelligence Resources Subject Tracer™. This will be added to Entrepreneurial Resources Subject Tracer™. This will be added to the tools section of Research Resources Subject Tracer™.