So I ran across this site a while back that let you create notes in your browser that could be saved, re-opened, even subscribed to via RSS.

Tony over at Ponderer.org has taken it a step further and combined it with Greasemonkey, the Firefox extension that lets you activate user scripts on just about any web site.

Using Greasemonkey, you can use the WebNote script to make notes on top of existing websites. This could be a great tool for designers who are reviewing concepts with a client or just want to make notes of something they see that they like. Check it out if you have a chance.

The permalink to the actual post about this seems to be messed up, so I will just include the important info here.

With the webnote gm user script, you can add notes to any web page. If you save the notes, they’ll be there the next time you browse to the page. They can also be viewed by anyone.

To create a new note, press ctrl+alt+n. To save all notes, press ctrl+alt+s.

The link below goes directly to the user script.