The Dewey Decimal System is an Ideal Taxonomy

In 1876, a librarian named Melvil Dewey created a simple classification system for library books.  His classification system was so simple that a grade school child can memorize its top-level taxonomy, and yet it is robust enough to be able to organize all topics in human thought.  The Dewey Decimal System is the most successful taxonomy ever developed.  In terms of information architecture, the Dewey Decimal System is:

1. Simple.  It uses only ten categories in its top-level taxonomy.
2. Robust.  It is able to organize all human knowledge into those ten categories.
3. Extensible.  It has been able to smoothly adapt to new ideas like recombinant DNA, computer technology, and a host of other concepts that simply did not exist in Dewey's time.
4. Deployment Independent.  The Dewey Decimal System works in single-room libraries, multi-floor libraries, and geographically dispersed libraries.
5. Automation Independent.  It works just as well with or without the assistance of computer technology.
6. Federated.  The over 100,000 libraries that participate are independent and yet collaborate on maintaining a unified taxonomy model for all libraries.
7. Interoperable/Virtualized.  It is possible to order a book at a local library but have it delivered using the interlibrary loan system.  This is because all the participating libraries use the same taxonomy, so information can be easily shared between organizations.
8. Adaptable.  The same taxonomy can be used to organize general libraries, medical libraries, physics libraries, and other specialized libraries.  Each library may emphasize different sections of the taxonomy, but they all use the same taxonomy.
9. Effective.  The Dewey Decimal System works, and the system is so efficient that a few libraries can support hundreds of thousands of books.
10. Scalable.  It can start small and grow indefinitely without disruption.
11. Media Independent.  It works equally well with books, tapes, disks, magazines, and stone tablets.
12. Governance Directed.  There is no Library Gestapo that enforces the Dewey Decimal System.  The libraries aren't locked down or frozen.  There is instead an advisory group of librarians who act on behalf of all libraries in adapting the Dewey Decimal System to novel circumstances.  They carefully adapt the system without breaking it. 

So, what can we learn from the Dewey Decimal System when we are establishing best practices for our top-level taxonomies?

1. Use no more than ten top-level categories.  In fact, it is best to start with no more than seven.
2. Use top-level categories that will never be obsolete.  Do not base the top-level taxonomy on org charts, departments, practice areas, or physical geography.
3. Focus on the big picture.  Don't just develop your taxonomy to support your intra net.  Develop your taxonomy to describe all the information buckets in your entire organization. 
4. Use a Federated and Collaborative Governance Structure.  Taxonomy development is no longer an Information Technology issue, but a whole-business issue. The Governance Team should be made up of stakeholders throughout the organization, be made up of no more than 12 people, and have the majority of people from non-IT departments.
5. Remain Technology Agnostic.  Do NOT tie your taxonomy to the constraints of whatever technology you are using at the moment.  The Dewey Decimal System does not need any automation at all, and certainly doesn't depend on a particular automation system.

More best practices to come...