Hypothes.is was the first layering app I used in a class and the app that got me started organizing and explaining examples allowing the annotation of online content. Hypothes.is allows the highlighting and annotation of web pages in a way that be shared publicly or with designated others. The service is free.
In supporting social annotation, I have most relied on my background in study behavior and generative learning not being able to offer research specific to the tools I was showcasing. This lack of research with social annotation may be changing as Hypothes.is has announced that Indiana University, a stalwart of the instructional design community, will be investigating the potential benefits of Hypothes.is in multiple classes. The description of the research questions may be helpful to those interested in the potential benefits of layering applications.