It seems only fair that if I'm taking next week to go to the Semantic Technology conference in California, I should be able to explain to my wife why it is that I'm going. The problem I have is that she asks technology people razor-sharp questions for a living, so it doesn't work to try to fudge the explanations. Although I've been writing here about the "Semantic Web" for a while now, I've been fudging about what it is I'm writing about and why I think it's important.
There are two words to talk about. The first is "semantic". Hidden within the word semantic is an asteism (word of the day: an asteism is a polite irony; a backhanded compliment). It's the same asteism inherent in the whole field of "artificial intelligence". To use the term "artificial intelligence" is to imply that machines are stupid. "Semantics" is the study of meaning, and to use the term "semantic web" seems to imply that the plain ol' web is devoid of meaning. What is really meant is that the plain ol' web is meaningless to those stupid machines. So the core idea of the Semantic Web is not just that meaning can and should be published, consumed and reused, it's that meaning can and should be published, consumed and reused... by machines.
The second word to talk about is "web". Note that the word is not "space" or "universe" or "world", each of which would have meant something useful and interesting. It's "web", a set of points connected by threads, which can be traversed and which can catch things. It's another asteism about the monolithicity and lack of connectedness of the semantic technology of today. Distribution is inherent in the word "web"; loading information into a big datase of facts is not a web. But the implicit question is what are the points that are being connected? The implicit answer again is "machines", but that, I think, is missing the point. Machines are not interested in meaning; they act as proxies for entities that really are interested in meaning- people, organizations, businesses, governments, schools.
So here's my answer. The Semantic Web is to be a social construct for the automated, distributed, publication consumption and reuse of meaning.
Note that I say "is to be" rather than "is". It is not clear to me whether or not the Semantic Web exists in a working or even incipient form today. It is clear to me, however, that the the Semantic Web must first and foremost be a social construct.
Whenever you see a discussion of the semantic web, there tends to be a lot of discussion about technology- RDF, OWL, tuples, microformats, and things like that. I've come to realize that equating the Semantic Web with those things is like equating the Roman Empire with legions, triremes, siege engines, arches, and roads. The Roman Empire used these instruments to exert power, of course, but that's not how it spread thoughout the western world. The Roman Empire was a social construct. In exchange for accepting Roman dominion and Roman Law, societies obtained the benefits of culture, communication and commerce. (Of course, if they chose not to, they were enslaved, but let's not take the analogy too far!)
The Internet has acheived global dominion using a construct analogous to that of the early Roman Empire. Participation in the Internet Empire requires acceptance of some basic rules (articulated by the IETF rather than the Roman Senate) and the benefits of participation clearly outweigh the costs. Instead of Latin, we have HTML and HTTP. The benefits received - culture, communication and commerce, are exactly the same.
The Semantic Web, by contrast, is still searching for a way to make its social construct an obvious benefit to all of its participants. If meaning and knowledge are valuable, then people will not be motivated to participate in a construct that only enables the distribution of that value. In particular, entities that expend effort to build and maintain the largest and truest stores of meaning and knowledge will have little incentive to participate.
In my last post, I talked about Google Fusion Tables and highlighted the attention that the designers paid to collaboration, control, and attribution. The reason I was excited is that Google Fusion Tables helped me imagine a world in which the Semantic Web social construct could deliver clear value to its participants and become a pervasive benefit to everyone.