The Firefox and IE extensions for Google Notebook are great. If you use Google Notebook and Firefox / IE and you don't have the extentions, go get them now. I've been using both extensions for months and I've never had a problem.
For me, Google Notebook is bookmarks on steriods. When I find a good page while researching or troubleshooting, I highlight the appropriate text, right click, and pick "Note this". A new note is created containing a link to the page and the highlighted text. When you're viewing your notes, the highlighted text is displayed for each note. If the text you selected is the only information you need from the page, then you don't need to load the linked page (cause the text that you need is right there in your Notebook!). You can categorize, tag, and annotate your notes. If you wish, you can make your notes public.
The extension window rests in the lower right corner by default, but you can "pop it out" to a larger, new window if you wish. If you want to search your notes, you have to load the full Google Notebook site. You cannot search your notes from the extension. IMHO, this is not a big deal.
Google Notebook has come in very handy. It's a great addition to your Developer's Toolbox.