When I heard Google is discontinuing their notebook plugin (among other products), I went looking for a replacement. Last night I found Sqworl, which launched late last year and is a way way better tool for research, documentation (APIs and such), and reference material (semantic web ontologies, for example). Looks like it has everything I need, except easy import/export of my existing bookmarks.
The site is:
For an explanation/review, see:
I created a simple sample documenting Google's famous development process: