Would researchers scrawl notes, critiques and comments across online research papers if software made the annotation easy for them? Dan Whaley, founder of the non-profit organization Hypothes.is, certainly thinks so. Whaley’s start-up company has built an open-source software platform for web annotations that allows users to highlight text or to comment on any web page or PDF file. And on 1 December, Hypothes.is announced partnerships with more than 40 publishers, technology firms and scholarly websites, including Wiley, CrossRef, PLOS, Project Jupyter, HighWire and arXiv. Whaley hopes that the partnerships will encourage researchers to start annotating the world’s online scholarship. Scientists could scribble comments on research papers and share them publicly or privately, and educators could use annotation to build interactive classroom lessons, he says. If the idea takes off, some enthusiasts suggest that the ability to annotate research papers online might even change the way that papers are written, peer reviewed and published. Hypothes.is, which was founded in 2011 in San Francisco, California, and is supported by philanthropic grants, has a bold mission: ‘To enable conversations over the world’s knowledge.’ But the concept it implements, online annotation, is as old as the web itself. The idea of permitting readers of web pages to annotate them dates back to 1993; an early version of the Mosaic web browser had this functionality. Yet the feature was ultimately discarded. A few websites today have inserted code that allows annotations to be made on their pages by default, including the blog platform Medium, the scholarly reference-management system F1000 Workspace and the news site Quartz. However, annotations are visible only to users on those sites. Other annotation services, such as A.nnotate or Google Docs, require users to upload documents to cloud-computing servers to make shared annotations and comments on them. Hypothes.is is not the only service that wants to make it easy for users to leave annotations across the entire web. A competing offering is a web annotation service from Genius, a start-up firm that began as a site for annotating rap lyrics. In April, it launched services such as browser plugins to help users to annotate any web page. But unlike Hypothes.is, the Genius code is not open-source, its service doesn’t work on PDFs, and it is not working with the scholarly community. On the scholarly side, the reference-management tool ReadCube makes it possible for users to annotate PDFs of papers viewed on a ReadCube web reader — but that software is proprietary. (ReadCube is owned by Digital Science, a firm operated by the Holtzbrinck Publishing Group, which also has a share in Nature’s publisher.) …”