Two interesting posts to Clay Shirky’s criticisms of hierarchical categories:
The problem is, the top-level categorization scheme actually means very little in actual use of the Library of Congress’ classifications. What does matter is something that Clay only gives a throwaway comment to much later on. When he discusses symbolic links on Yahoo (where they can place “Books and Literature” in Entertainment though it primarily “belongs” in Humanities), he gives this aside: “The Library of Congress has something similar in its second-order categorization — “This book is mainly about the Balkans, but it’s also about art, or it’s mainly about art, but it’s also about the Balkans.” Most hierarchical attempts to subdivide the world use some system like this.”
Actually, the “second-order categorization” he’s referring to are the LOC’s Subject Headings. Which, in our digital world, are actually what people *use* when trying to find books. So, if I’m doing research on the history of environmental degradation caused by the development of the city of San Francisco, I don’t need to figure out some single primary concept (“history,” “environment”, “san francisco”) and hope for the best. As this listing of Gray Brechin’s “Imperial San Francisco” demonstrates, I could find this book through any number of subjects…
Group tagging is the next big frontier, or one of them. This work will include, of course, spam defenses like “Only show me things tagged ‘design’ by people I know, or people they know.” As we know from years of bitter experience, it’s impossible to create a source of group-created value with low barriers to entry without also inviting system gaming.