As a data producer, I want to know when people comment on my data without having to look at the dataset/file/etc.
(example from one of our competitors: http://help.osf.io/m/collaborating/l/524111-commenting)

Acceptance Criteria:
1. When a comment is left on an object, the owner of the object as well as the people who belong to the space and have permission to view comments get an event about the comment in their event feed.