Web 2.0 and flickr

It seems to me a natural consequence of the increasing bridging of traditional data sources into RDF is that the number of "walled gardens" of RDF is increasing. Walled gardens are areas from which there is no escape, and while they certainly have their uses (in particular controlling who can access what), they erode the overall usefulness of the system as a whole, by meaning that you literally can't get to there from here.

Examples of RDF walled gardens include the FOAF generated by such systems as tribe.net and livejournal. While it is useful that these sites are exposing data in a machine readable web 2.0 format such as RDF/FOAF, the inability to link to people, resources and interests outside the walled garden represent a significant barrier to interoperability. I am the same person in my blog RSS feed, my flickr photo feed, my del.icio.us feed , my tribe FOAF and my hand-edited FOAF, but only the last can I link to the others, despite the fact that they are all in the same format.

In the last two-three years a huge amount has been written about tagging and folksonomies, much of it with the bright-eyed enthusiasm of those who haven't seen the present state of affairs in a broader light; but where is the fight-back from the formal classificationists, who hither-to ruled unchallenged in this area? Have such giants as the Library of Congress and the Dewey Decimal System fallen at the first hurdle?

Tagging is the assigning of arbitrary tags to content by amateurs (typically content creators, editors or readers) and folksonomies are systems built from the ground up using these tags. Tags have no formal meanings and there are no constraints placed upon them. Folksonomies are central to systems such as flickr, del.icio.us and the whole web 2.0 approach.

Formal classifications, such as the the Library of Congress and the Dewey Decimal System are rigorous systems in which trained individuals assign subject categories to content. Each category has a description and is long lived—categories don't change even when the words used to describe the topic in popular culture change. Thus the LoC still calls cars automobiles, because that's what they were called when they first entered the system.

This 30 minute recording with Alfred Essa, Executive Director of the .LRN Consortium, gathers his thoughts on open source, blogs, podcasts, java, .LRN and a range of other topics.