Soon after he created the World Wide Web, Tim Berners Lee turned his attention to the semantic Web -- a Web of data rather than documents. Google is now rolling out their first step in that direction, the Knowledge Graph.
Google's 2010 purchase of Freebase and Metaweb, the system used to create it, was a key step toward Knowledge Graph. Freebase is a semantic database, which knows the attributes of entities and the relationships between them. For example, Freebase knows that Larry Press is a person and the value of his city of birth attribute is Pasadena, California (not Pasadena Texas).
Google started with the Freebase concept and added data to create the Knowledge Graph database, which now contains 500 million entities with 3.5 billion attributes and connections.
Let's look at an example. I started with a vanity search for myself, and the following profile was displayed on the right hand side of the screen:
Note that it did not know the value of any of my attributes, it just returned a link to my Google Plus profile and the first few sentences of my most recent posts. I guess I am not one of the 500 million entities included in Google's Knowledge Graph.
Next I searched for George Washington, who is a bit better known than me, and is included among Google's 500 million entities.
In this case, it knows his nicknames, date of birth, etc. Since he is not just a person, but a president, he also has a vice president attribute. It also knows that he died at Mount Vernon, which is another entity that is included in Google's Knowledge Graph:
While the Knowledge Graph was developed using the Freebase tools, Google did not import the user-contributed Freebase data. (I am in Freebase, but not in the Knowledge Graph). That says Google is abandoning the Wikipedia-like openess of Freebase, in which users could add entities and change the values of their attributes, for a database that is currated in house. That will limit its growth and its "Internetness."
This is an interesting announcement, but Google is not the only player in the Web of data game.
Apple has attracted a lot of attention with Siri, a speech-driven application that answers questions by querying Wolframalpha, another semantic database system. Knowledge Graph gives Google an answer to Siri and Wolframalpha. (Wolframalpha goes further, incorporating a powerful symbolic math engine).
Microsoft is also working on the semanticly rich Web of data. They characterize Bing as an "answer engine" rather than a "search engine," and Microsoft Research has a Semantic Computing Intitative. Microsoft will no doubt incorporate their work into Bing.
The Web is getting smarter -- we may move from today's Web of documents to a Web of data and eventually a Web of knowledge (an ill-defined wannabe buzz word I've heard). It makes you wonder what it will be like in fifty years.