Hi, good work with this, can be really useful.
I have 3 feature requests however that I think are really important (before I implement this into my site forums!):
2) There ought to be a way to edit your own note direct from the post. Edit link after your own notes?
3) In the admin interface, moderators and admins alike should be able to overview all notes by threads and admins should have power to delete / edit all from here.
Also, why does the word, 'Quote' appear after the add note / hide note link? http://i.imgur.com/A6K1y.jpg