Rated 5 out of 5 stars

Really, a great extension.
Hope it will be soon compatible with firefox 4.0. Something I miss a little is a (customizable) popup menu on selected content when editing (saved) pages with options such as Highlight, Add note, Add inline note, and so on. 
A more advanced feature would be the possibility to merge and split scrapbooks in an easy way. It's indirectly possible now but not so straightforward, you have to resort to import/export functionalities.
Most of keyboard shortcuts does not work for me, maybe due to conflicts with other extensions.
To use this extension at its full extent it's worth to give a look at the pdf Tutorial.
Thank you for developing it!

This review is for a previous version of the add-on (1.3.7).