This one is cool. I just have checked out it and it works perfectly and is exactly what I was looking for. I would recommend you a few suggestions which I think would add more value to the script.
First of all, create a separate ANN thread for this. That would help to reach more users.

1. Change the color of "Add Note" to blue.
2. When I visit the user profile, I can't see the note. Possible to put it there too?
3. When we re-write the note, I'm expecting to see the previous text in the input box.
4. I would hate to see other people's notes in public. So, consider not importing them and making them public.
.

These are my personal suggestions/recommendations if you are considering further development.