I am creating a subscription site.
As a feature of the site I would like subscribers to be able to write notes about any portion of the content (in the context of the content - not as a post comment at the end) and then see those notes again when they visit the page again.
Ideally this would be on a per-subscriber basis (however the concept of having both public AND/OR private notes might be good too).
The main goal is to replicate the way a user might underline or write themselves notes in the margins of a course book if the content were non-digital.
Ideas or suggestions?