Opinion - Categorisers are second guessing future trends. With more and more users tagging information with their own terms, creating a taxonomic structure to keep up with change is impossible, argues David Tebbutt.

Clay Shirky, adjunct professor at New York University and internet expert, notes that categorisers need to be both mind readers and fortune tellers.

What a great description of the difficulties they face. The pesky world keeps changing, and at such a pace that it's impossible to keep up. By the time the taxonomies have been carefully re-crafted, the world has moved on again.

On mind reading, the user has to know, guess at or refer to the controlled vocabulary to find what they want. Or some kind of synonym mechanism needs to be in place. Either way, the categorisers are second guessing the users, while not polluting the taxonomy.

Fortune telling, in this context, is about predicting the future. It's impossible to create a taxonomic structure that can cope with all future change. Libraries are a great example. No doubt you've read about the preponderance of Christianity in the Religion section of the Dewey system, or the prominence of the Balkan Peninsula in the History section of the Library of Congress. Both had lots of books written about them, thus giving them prominence in the classification system. Hardly an objective reflection of the real world.

Having said this, traditional systems have their place and it would be madness to dismantle them without having something better in their place. But interesting things are happening on the internet, with users tagging information with their own terms. No consulting a controlled vocabulary, just an instinctive choice of appropriate words.

Thomas Vander Wal coined the term 'folksonomy' to describe the approach. If enough people apply tags to a web-based entity, then it's easy to see which terms are the most popular. And the likelihood of a successful search is increased.

An ...