Late last month, Google’s search engine got significantly smarter.
A store of information dubbed the "Knowledge Graph" now adds useful context and detail to the list of links that Google serves up. Searching for certain people, places, or things produces a box of facts alongside the regular results. The Knowledge Graph is already starting to appear in a few other Google products, and could be used to add intelligence to all of the company’s software.
"Search was mostly based on matching words and phrases, and not what they actually mean," says Shashidar Thakur, the tech lead for the Knowledge Graph in Google’s search team. Thakur says the project was invented to change that.
The Knowledge Graph can be thought of as a vast database that allows Google’s software to connect facts on people, places, and things to one another. Google got the Knowledge Graph project started when it bought a startup called Metaweb in 2010; at that time, the resource contained only 12 million entries. Today it has more than 500 million entries, with more than 3.5 billion links between them.
Such a stock of knowledge about the world should have uses beyond just helping people who are searching for facts online. Thakur says that the Knowledge Graph has already been plugged into YouTube, where it is being used to organize videos by topic and to suggest new videos to users, based on what they just watched. It could also be used to connect and recommend news articles based on the specific facts mentioned in stories, says Thakur. "Knowledge Graph is a very general resource; it’s like a ground truth we can refer to."
When a person searches on Google, the conventional results are based on algorithms that look for matches with the terms rather than the meaning of the information entered into the search box. Google’s algorithms first refer to data from past searches to determine which words in the query string are most likely to be important (based on how often they have been used by previous searchers). Next, software accesses a list of Web pages known to contain information related to those terms—known as reverse indexes. Finally, another calculation is used to rank the results shown to the searcher. With luck, what they’re looking for will be found somewhere in those pages.
Google’s new approach, made possible through the Knowledge Graph, is to try to interpret what a person is asking about in a much more sophisticated way and directly retrieve relevant information.