I absolutely LOVE Plugin Notes. I downloaded it after reading that post by Chris Coyier, and subsequently your comment on it. Before I got to your comment, I was thinking, "Geez, putting notes on plugin installs would be awesome..."
Great job on the plugin. At my job I work with one other WP developer on our sites, and Plugin Notes has been invaluable in leaving notes for each other on modifications, explanations... everything. Thanks for the plugin!