Excerpts from an interview in Technology Review:
The common thread to the Semantic Web is that theres lots of information out therefinancial information, weather information, corporate informationon databases, spreadsheets, and websites that you can read but you cant manipulate. The key thing is that this data exists, but the computers dont know what it is and how it interrelates. You cant write programs to use it.
But when theres a web of interesting global semantic data, then youll be able to combine the data you know about with other data that you dont know about. Our lives will be enriched by this data, which we didnt have access to before, and well be able to write programs that will actually help because theyll be able to understand the data out there rather than just presenting it to us on the screen.
Suppose youre browsing the Web and you find a seminar advertised, and you decide to go. Now, there is all sorts of information on that page, which is accessible to you as a human being, but your computer doesnt know what it means. So you must open a new calendar entry and paste the information in there. Then get your address book and add new entries for the people involved in the seminar. And then, if you wanted to be complete, find the latitude and the longitude of the seminar, and program that into your GPS [Global Positioning System] device so you could find it.
Its very laborious to do all this by hand. What you would like to be able to do is just tell the computer, Im going to this seminar. If there were a Semantic Web version of the page, it would have labeled information on it that would tell the computer this is an event, and what time and date it is. And it would automatically add your travel to your event book. It would add the people to your address book, and it would program your GPS to give you directions. It would have the relationships between the event and the various people chairing it. And those people would have Semantic Web personal pages, which contained information about how you could contact them.
Your address book can now grow from a closed repository of private data to a view on the people-related data in the world.