The Semantic Web, in theory, is a brilliant idea. For a starting point to read all about it, check out its entry on Wikipedia. In a nutshell, the Semantic Web is about bringing meaning to data and web pages. The ultimate goal appears to be make data work without (and on behalf of) humans. At the moment, if my car starts feeling ill, the computer displays a warning light on the dashboard. I ignore the warning light until the car all but stops working. Then I phone the garage, get it towed in and they repair it. In a Semantic Web world, my car wouldn’t let me be so flippant. It might still display that warning light to humour me, but it will also send a message to the garage and book itself an appointment to repair the failing component. If fully automated driving ever takes off, it will take itself to the garage and come back home when its ready
OK, so there are probably more realistic examples to demonstrate the benefits of a Semantic Web, but the principles (in simple terms) are there:
- a universal method to describe data (ontology)
- a standard language to store data (XML)
- a common mechanism to move data (web services)
In my optimistic example, cars will use a universal ontology to describe their ‘bits’ and associated information to trigger alerts when something goes wrong. That data will be stored using an agreed XML schema that all garages can read and willl be transmitted to the garage (subject to wireless network being available) using a published web service. Similarly, all garages will use a universal ontology, XML schema and web service to make their diaries available for cars to locate free slots and book in appointments… and so it goes on
Two of those principles are achievable and already being adopted in many business and consumer systems. One isn’t. There will never be a universal method todescribe all data and if there were, it would go the way of Google’s PageRank algorithm – successful for as long as it takes for the system to be gamed. Search Engine Optimisation would be replaced with a new black art: Semantic Web Optimisation
As long as human nature is involved in designing (and using) an ontology, there will never be agreement. I have just finished reading a wonderful book – Glut: Mastering Information Through The Ages. It documents the attempts to classify and organise information literally since records began, and highlights the common cause of failure – different perspectives reach different conclusions. Many people reference the library as a shining example of how taxonomy can work, citing the Dewey Decimal system. The Dewey Decimal system was first created in 1876 by Melvil Dewey. Dewey gave higher status to Christian religions (sections 200 through 280) than all others (Judaism and Islam are given just one section each – 296 and 297 respectively). I wonder what religion he belonged to? His design was not without context and therefore not universal…
And history appears to have taught us nothing about our lack of ability to work on anything universal. In the 18 August 2007 issue of the New Scientist magazine, there were two articles covering the same piece of the planet. The first article questioned whether or not a tipping point has already been reached with regard to climate change. Concern focused on the melting Greenland ice sheet and how the consequences will affect us all. In the news section, a small article covered ‘Arctic monkeying’, the race to claim ownership of a seabed structure running from Greenland to Russia. Apparently, a Russian submarine planted a flag on the seabed beneath the North Pole. Canada is building a military base and deep-water port to govern the emerging North-West passage (about that melting ice sheet…) Denmark has sent researchers to assess its claim on the untapped oil and gas reserves that just happen to lie in the region under dispute… amply demonstrating why we are doomed to suffer the consequences of climate change. For goodness sake, we can’t agree on a single currency, spoken language or even agree to all drive on the same side of the road. Diversity is a core part of what it is to be human. Universality requires human nature to exit through the door to the right (about that talk of climate change…)
So what will become of the Semantic Web?
XML and web services continue to spread through systems and applications. Even Microsoft, never the first to sign up to an open standard 🙂 has adopted XML formats in its latest Office applications, and web services are used to communicate between desktop applications and services/online services.
Ontology is the difficult member of the semantic family – unfortunate because ontology is the ‘semantic’ in The Semantic Web.. Hierarchical ‘top-down’ taxonomies continue to battle with networked ‘bottom-up’ folksonomies and history suggests such conflict is a necessary feature (not a bug) of evolving systems. User tagging has proven unexpectedly successful, thanks to Flickr and blogging, and demonstrated the value of folksonomies. But inconsistencies remain rife. If I want to Technorati tag a blog post about Web 2.0, do I use web 2.0, web-20, web2.0, web20… Perhaps that’s the trade-off we will have to accept – forget striving for a universal method and instead learn to work with local variants and their different contexts. Accept that the results won’t be perfect. Just like the real world 🙂
Without doubt, the use of metadata to enhance search results and create new systems has the potential to disrupt and is attracting huge attention. You can see some of Google’s work on multi-faceted search (pivoting results based on classification category) over at http://www.google.com/experimental/index.html. Microsoft Research published research on ‘object-level vertical‘ search algorithms although a more exciting demo can be found at TED – Ideas worth spreading: using Photosynth to combine photos (found through their tags) into a 3D virtual world.
Nicholas Carr, yes he who said I.T. doesn’t matter but can’t seem to stop writing about it anyway :-), perhaps identified where the semantic web will come to life – the real Web 2.0: the datacenters competing to host our information in the ‘cloud’. Will the providers of online services become the gate keepers to different semantic webs?
- The Semantic Web (Wikipedia entry)
- Weaving the Semantic Web (Business 2.0 article, July 2007)
- The Semantic Web (or (original article, authored by Tim Berners-Lee and friends, May 2001)
- Glut: Mastering Information Through The Ages (by Alex Wright, published 2007)
- The Real Web 2.0 (blog post by Nicholas Carr, April 2007)
- Demoing Photosynth (TED Talk, March 2007)
Technorati tags: semantic web; web 2.0
I almost agree with your points. The main difference is that the third challenge is not that we agree on a universal ontology, but rather that we all agree on a "semantically transparent" language in which to describe what WE mean, from our unique perspective. For that one must turn to light-duty (OWL and its dialects) or heavy-duty (first order logic) logic languages. Then, automated systems can reason about what they find out on the web.