Google has added support for labels to Google Notebook. The move isn't surprising. You can use labels to organize Gmail, Google Documents, RSS feeds in Google Reader, and the list goes on. What is a bit surprising is that it's taken so long to roll out support for labels in Google Notebook.
Labels are automatically imported from your Google Bookmarks settings, if you use Google Bookmarks. You can then sort or filter your notes by label using either the Google Notebook web page or the Google Notebook browser plugin.
Via (Google Operating System.)