Maybe this is common information that everyone knows, but I’d never seen it before last week when I did it by accident. When you right-click a folder icon in your Firefox Bookmarks and select Copy you get the folder name, the URLs under that folder name, as well as the additional folders under that folder and their content all placed on the clipboard.
For example, if I select the folder shown below and select Copy it will place the Cooking folder title on the clipboard as well as the URLs of the items in the folder.
Here’s what can be found on the clipboard:
One other great use of this tip is that if you right-click any of the items at the top of the Bookmarks folder, such as Organize Bookmarks and select Copy, your complete library of bookmark URLs will be placed on the clipboard as well as the folder names.
This appears to only work in Firefox 3.0 (I have 3.0.3 at the moment). I tried it on my laptop that still has 2.something and it did not work.