As a teacher, I want to be notified when:

• Students make annotations on assignments so that I can keep up with overall course activity, and answer student questions in a timely manner
• Someone replies to my annotation so that I can facilitate conversations with my students

As a teacher, I would like Hypothesis to send a notification when:

• I want a particular student to know about or reply to an annotation I've made, so I can facilitate the conversation and keep it alive throughout the semester
• I want the whole class to know about an annotation I've made, so I can ensure all of my students are aware of important pieces of the document we're reading

As a student I want to be notified when:

• Someone replies to my annotation, so that I can engage in discussion with my teacher and classmates

As a student, I would like Hypothesis to send a notification when:

• I tag my teacher, so I can ask a question of my teacher as I'm reading
• I tag a classmate, so I can ask them a question, let them know I agree with their point, and generally engage them in conversation about the reading

Some lessons learned from custom notification setups: https://docs.google.com/document/d/1zSkMjYsAT-hA0ZuX2JgsKq-JklgPAKzjuJ6aIIxJdyQ/edit#

Considerations for Canvas:https://github.com/hypothesis/support/issues/112

Previous issue: #235