I didn't read »Ambient Findability« yet, but from a look at the table of contents I can tell that Peter Moreville's new book going to be interesting. Moreville was very influential with his »Information Architecture for the World Wide Web« several years ago. Among the many topics he addresses in his new issue is the question of Folksonomy vs. Ontology where he seems to stress that both approaches are valid and should probably coexist.

»Tagging« is something that has been done for years by librarians: it's the act of associating keywords with certain texts, books, or any artefact in the context of some »collection«. The idea is that these keywords will help users to find the items they are looking for - or the items they might be interested in even if they didn't know that they existed. »Folksonomy« is a term coinded by Thomas Vander Wal to describe the informal social categories that emerge when people attach keywords (»tags«) to photos, texts and other stuff on the web - what used to be the »priviledge« of librians becomes a social activity.

Flickr and del.icio.us are among the online project that most successfully applied this technique to large collections of digital items that are accessible via the WWW (Flickr terms itself as a photo sharing community, while del.ici.ous is a place to share bookmarks). With large relational databases behind, it's only a matter of milliseconds to get the subset of items that's associated with the tag that you chose during search. In the arts context, look at runme.org to get an impression of how powerful this approach is. With technorati and similar services and almost ubiquitous »behind-the-scenes« exchange between web servers (so-called »web services«), »tagging« has become a very common means to glue together what (hopefully) belongs together in today's World Wide Web.

Another kind of »glue« are the so-called »Ontologies«. Putting aside the headaches that the term »ontology« might cause in some philosophers, we could describe an »ontology« as a formal representation of the shared knowledge in a subject domain. Ontologies are very common in some sciences (bio sciences, medical science, cultural sciences, etc.). More recently, there have been attempts to apply this kind of »knowledge management« to commercial purposes too. Ontologies also play a major role in the plans of the W3C (World Wide Web Consortium) for the so-called »semantic web«.

Typically, you have a set of classes of possible objects together with the possible relations between these objects as well as their attributes that are described in a formal manner. Now, things that are know about a certain topic can be expressed within this formal structure allowing for easy retrieval of information and even automatic »reasoning«. This may sound familiar: in a way, this is an extension of the so-called »expert systems« of the 1970s that were intended to mimick an experts reasoning given a certain »knowledge base«. [- to be continued -]

-- Christoph Pingel