Firefox: Organize bookmarksJuly 15, 2011
In Firefox 5.x, the Organize Bookmarks option has gone — it’s been replaced with Show All Bookmarks.
To see the complete list of your bookmarks so that you can arrange them into folders, import/export them etc., go to Bookmarks > Show All Bookmarks.
I’m not sure why they changed the name — Organize Bookmarks worked well for me. My first thought on seeing Show All Bookmarks was that everything I had bookmarked would open in new tabs!