October 24, 2005

Once upon a time: The 'G' Story

It began with an argument. When he first met Larry Page in the summer of 1995, Sergey Brin was a second-year grad student in the computer science department at Stanford University. Gregarious by nature, Brin had volunteered as a guide of sorts for potential first-years - students who had been admitted, but were still deciding whether to attend. His duties included showing recruits the campus and leading a tour of nearby San Francisco. Page, an engineering major from the University of Michigan, ended up in Brin's group.

It was hardly love at first sight. Walking up and down the city's hills that day, the two clashed incessantly, debating, among other things, the value of various approaches to urban planning. "Sergey is pretty social; he likes meeting people," Page recalls, contrasting that quality with his own reticence. "I thought he was pretty obnoxious. He had really strong opinions about things, and I guess I did, too."

When Page showed up at Stanford a few months later, he selected human-computer interaction pioneer Terry Winograd as his adviser. Soon thereafter he began searching for a topic for his doctoral thesis. It was an important decision. As Page had learned from his father, a computer science professor at Michigan State, a dissertation can frame one's entire academic career. He kicked around 10 or so intriguing ideas, but found himself attracted to the burgeoning World Wide Web.

Page didn't start out looking for a better way to search the Web. Despite the fact that Stanford alumni were getting rich founding Internet companies, Page found the Web interesting primarily for its mathematical characteristics. Each computer was a node, and each link on a Web page was a connection between nodes - a classic graph structure. "Computer scientists love graphs," Page tells me. The World Wide Web, Page theorized, may have been the largest graph ever created, and it was growing at a breakneck pace. Many useful insights lurked in its vertices, awaiting discovery by inquiring graduate students. Winograd agreed, and Page set about pondering the link structure of the Web.

It proved a productive course of study. Page noticed that while it was trivial to follow links from one page to another, it was nontrivial to discover links back. In other words, when you looked at a Web page, you had no idea what pages were linking back to it. This bothered Page. He thought it would be very useful to know who was linking to whom.

Why? To fully understand the answer to that question, a minor detour into the world of academic publishing is in order. For professors - particularly those in the hard sciences like mathematics and chemistry - nothing is as important as getting published. Except, perhaps, being cited.

Fair enough. So what's the point? Well, it was Tim Berners-Lee's desire to improve this system that led him to create the World Wide Web. And it was Larry Page and Sergey Brin's attempts to reverse engineer Berners-Lee's World Wide Web that led to Google. The needle that threads these efforts together is citation - the practice of pointing to other people's work in order to build up your own.

Which brings us back to the original research Page did on such backlinks, a project he came to call BackRub.

At the time Page conceived of BackRub, the Web comprised an estimated 10 million documents, with an untold number of links between them. The computing resources required to crawl such a beast were well beyond the usual bounds of a student project. Unaware of exactly what he was getting into, Page began building out his crawler.

The idea's complexity and scale lured Brin to the job. A polymath who had jumped from project to project without settling on a thesis topic, he found the premise behind BackRub fascinating. "I talked to lots of research groups" around the school, Brin recalls, "and this was the most exciting project, both because it tackled the Web, which represents human knowledge, and because I liked Larry."

Extracts from The Birth of Google, Wired Magazine

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