We’ve been trying to explain partial understanding since at least as far back as the 1998 Extensible Languages note, but the The Fate of the Semantic Web report from Pew still reflects the perception that the Semantic Web will never work because it requires global agreement on one big ontology.
In Tim Berners-Lee’s talk at the gov 2.0 Expo, he gives a wonderful illustration using a bag of potato chips.
On the bag of potato chips, he shows various vocabularies in use:
- the plain English “potato chips” on the front — note that’s U.S. English; in the U.K., it would be “potato crisps”.
- the nutrition information on the back, standardized by the U.S. food and drug administration.
- some allergy information that many people don’t pay any attention to, but those with allergies read very carefully.
- the UPC code that can be read by any retail checkout machine in the world
- some numbers on the bottom edge of the package that make no sense to him whatsoever.
He points out that people don’t go “Eek! I won’t eat that! I can’t make sense of those numbers at the bottom.” But object-oriented systems and XML Schema checkers typically do just that. Most people just look at “potato chips” on the front and maybe take a quick look at the number of calories and munch away. He goes on to explain how linked data is not waiting for the whole world to agree on vocabularies for everything; it’s not like that… it’s like a bag of potato chips.
p.s. The bag of chips came from a lunch discussion, but I think the illustration of multiple vocabularies used in product packaging goes back to a paper he wrote in 2008 with Lalana Kagal, The Fractal Nature of the Semantic Web.