Google Notebook

I found today that Google has released Notebook.  Notebook is similar to in that it will store information that you find online and has the ability to share with others.  I like the feature that allows you to hide a link from everyone, anyone not on your contacts, or make it visible to all.  I also enjoyed the fact that it went right to the Firefox extention page when I asked to download it, and that the extention is very very easy to use.