http://www.extensionsmirror.nl/index.php?s...16&hl=scrapbook
NB: they are other extension doing a more or less similar job (http://www.extensionsmirror.nl/index.php?showtopic=1048&hl=scrapbook), but I found scrapbook the most useful.
An other solution is using Acrobat Pro (5, 6 or 7), capturing the web page as pdf and highlighting / commenting the pdf, but Acrobat Pro is expensive.
The files saved by scrapbook are in html format (+ gif, jpg, css, etc), so they can be searched for with desktop search software (eg: Copernic)
Hope you will find as useful as I do!
Edit: You could also simply use a WYSIWIG html editor
