Social bookmarking has been around for awhile. Making bookmarks public is a difficult pill to swallow. I do like the concept from a collaborative perspective. I wonder, and need to do it to learn about this, if I can keep some things private and others public. Or is it best to run two accounts, one for personal and one for private. A problem with that is that some sites would overlap. Sigh. Big Brother has become a fabric of our society.
The advantages to tagging is that it would be far better than the folders. I have useful sites I probably never see or duplicate bookmarking because I forget where they were. An important element is tagging accurately. That will take time, observation, and lots of practice.