Hypothes.is is a versatile and user-friendly web annotation platform and browser extension. With Hypothes.is, you can annotate text on any web page or any web-hosted pdf that has been OCR-optimized. If you have images or other media to annotate, you can create a "page note" on Hypothes.is, but for more advanced and specific media annotation, another tool from the toolbox may work better.
Here are links and instructions about getting started in Hypothes.is.
How do you discuss the reading if you can’t meet in person? In this PowerPoint presentation on “Collaborative Annotation,” Queens College Library's Emerging Technologies and Digital Scholarship Librarian Dr. Leila Walker shows how collaborative annotation tools can help cultivate critical reading habits and develop close reading skills, and indicate where students might need extra guidance to understand the material.
This is a beginner-to-intermediate video overview from a Hypothesis power-user, with great information on how to create and manage annotations (including adding media) as well as groups and other features.
If you want your annotation public or private, keep the Hypothes.is bar set on the appropriate setting. it is also possible to create or join a group where only the group users see the annotations.