I think tagging is a wonderful tool that can be used to help browsers find what they're seeking. I haven't been using it on these posts mainly due to my bad memory. I usually finish typing and then forget that I can add labels. I think tagging is possible in libraries, as stated on the 23 Things site it is similar to subject headings. I think they are very similar. I wonder if there would be any way to view/track patrons who would be trying to tag inappropriately. (C'mon, there's always someone!) I say encourage it if we can monitor it.