In essence, the semantic web is a web capable of understanding the content of web pages. You might think computers already do this, but while they understand how to display a web page, they can only guess at what the page is about. The idea of the semantic web is to find a way for computers to understand the content and not just the structure.
How Search Engines Work
Currently, search engines like Google rely on keyword phrases found throughout a web page to figure out what the page is about. For example, this article has the word 'semantic' repeated multiple times and the phrase 'semantic web' coming up a number of times. When Google's search engine sees this, it starts thinking the article is about the semantic web.
This works a fair amount of the time, but sometimes it can come up with some rather strange results. Most of us have come across rather peculiar results when searching for something specific. The idea of creating a more semantic search engine is to teach the computer to understand what is on the web page in order to find better results.
Creating the Semantic Web
It's important to note that there are two different approaches to creating a semantic search engine and a semantic web. One approach is for websites to 'tag' their content, in essence telling search engines what the content is about -- like a miniature book report about the web page. Another approach is for the engine to be sophisticated enough to scan through the document and figure it out on their own. Of course, this is easier said than done.
The biggest fault with the idea of 'tagging' content to give search engines a hint to the content's subject is that it begs to be abused. It is a great system if everyone is using it honestly, but there are a lot of snake oil salesmen out on the web who would use any means possible to get you to their sites. But these same sites already do the same, pulling out all the stops to trick search engines into thinking their keyword phrase is the best, so we might just be par for the course on that one.
If we could do the same without the tagging, that's a win-win. Not only would it keep websites from needing to do massive updates in order to include semantic tags, it might keep the search engine one step ahead of the snake oil salesmen.
But that's a tall order. Imagine trying to teach a computer to decide which is better: Fyodor Dostoevsky's Crime and Punishment or Charles Dickens' A Tale of Two Cities. Google's recent gaff with displaying Jesus Christ's birth date as being in the year 1963 shows how easy it is for a computer to get it wrong.
Is the Semantic Web Really Web 3.0?
Many people feel Web 3.0 will be the semantic web. If we consider that Web 1.0 was about using the web as a tool, and Web 2.0 is about integrating ourselves into the web, then it seems logical to think Web 3.0 should be about teaching the web to understand us.
But it is a bit too early to make presumptions about what Web 3.0 will be. No doubt, it will be used as a buzz word for the semantic web and other advances that people want to draw attention to in the future. But the next true generation for the web could very well go in a totally different direction, such as a virtual world taking over for the web browsers. And no doubt Mobile 2.0 will have a lot to say about the future of the web.
So What Is the Semantic Web? And How Do We Get There?
As I mentioned at the beginning, the semantic web is the idea of teaching the web -- which is to say teaching the next generation of web search engines and web browsers -- how to understand the content rather than just the structure on the web. It is teaching the engines to read, understand, draw out the essence and be able to deliver it to us.
A primary use of this would be better search engines, but it also has other uses. Web browsers and search engines would be able to answer simple questions by mining the web for the answers. You might also be able to highlight a phrase in your browser and have it come up with more information about that phrase -- such as reading an article about horses, highlighting a phrase about the proper care for a horse, and having the browser pull up more information about that subtopic.
But it is still a long road before we get there, and it is a road with many different paths.
