Reminds me of RES (Reddit Enhancement Suite) which I used to use a long time ago to do the same thing. One cool thing RES used to do was (if I remember right) when you clicked on the tag/note placed on the user it would take you to the comment when you first attributed that tag/note.

On one hand I kinda miss doing stuff like that and would like a RES for Hacker News but on the other hand I feel like cyber stalking is out of fashion these days.