So far I think Google Notebook is pretty cool and I really like the integration with Firefox. But I'm now even more miffed at the disconnect in Google's bookmarking strategy. They have a bookmark system on your personalized search page. This one behaves much like delicious, with tags and what not, and a clever bookmarklet. But it is not connected to the bookmarks content on your personalized homepage??!? That one is completly separate somehow.
Now here comes notebook, which is much slicker, but is separate from the rest and doesn't support tagging
at all (or RSS from what I can see). Instead it has a more traditional folder style system. That is so not like gmail, where folders are bad.
So in conclusion I think this is a good first (or, hmm, 3rd) attempt but it still falls short of the uber online bookmarking system I've been waiting for. I'm sure they will get it right in the next rev.