In 2012, when Knowledge Graph first debuted, its visual was a panel that appeared on the side of the screen alongside the standard Google search results. The information in the panel ranged from biographical data such as spouse (for a person) or architect (for a building) to noteworthy dates. Based on the most frequent information Googled about a person, a team was tasked with constantly updating the panel. For instance, they have honed in so well on what people want to know about Tom Cruise (hint: height) that the information shown in his knowledge graph answers 37% of the follow-up queries that people have about him.
"When you're searching, you're using words, and we [had been] finding you documents that contain those words," says John Giannandrea, vice president of engineering at Google and one of the brains behind the Knowledge Graph. "But computers didn't understand what it was that you were searching for." Google wanted to impart knowledge--the who, what, why, and how of a person, place, or even an abstract philosophy.
Since Knowledge Graph was unveiled, its creators have been steadily releasing updates that will not only change how we get information, but also were inspired by users' habits. "As people move to mobile devices, they want to type less and get more answers," says Giannandrea.
Not only does the Knowledge Graph make smartphones smarter, but it also allows users to get a richer experience out of their search. In an update that Billboard hailed as "impressive in its breadth," last month Google changed its musician searches. Before, if you entered a musician's name, a search would return basic biographical information. Now, specific songs are also listed. "Often Google searches are a proxy for what someone is really looking for," says Giannandrea. "For instance, when searching for an artist, what someone really wants to know is the name of the song they just heard on the radio or in a commercial. Now they can find that in the Knowledge Graph."
The comparison feature, which was added in September, emphasizes the sheer volume of detailed information available on each entity. In some searches, the side panel has been moved top and center and shows a side-by-side comparison of, for example, the nutritional values of an apple and banana or the architectural stats on the Empire State Building versus the Eiffel Tower.
It also shows the interconnectedness of the system. "Traditionally when people look at databases, they are vertical and about one thing. This is a graph, so everything is connected to everything else. If a movie features a song, the song is connected to an artist. Barack Obama is not only president, but also an author," says Giannandrea, who goes on to joke--"It's six degrees of Kevin Bacon, but for everything!"