MONIKA HENZINGER ON ALGORITHMS

7. Still Searching (After All These Years)

by Susannah Patton

Monika Henzinger, born in Bavaria, Germany, enrolled at Germany's University of Saarbrucken in 1985 and promptly fell in love. The object of her affection was an arcane branch of computer science. "As an undergrad, I fell in love with the efficient algorithm," Henzinger says enthusiastically. "This was something elegant and fun. I have always liked solving problems, and finally I had found my true calling."

Henzinger, now 36, went on to earn her doctorate in computer science from Princeton University. But it was while teaching courses on her beloved algorithms at Cornell University when she had a flash. "I realised that efficient algorithms were fun but not very useful to the world any more," she says. Soon after, she left the academy and turned her attention to something that would be: Web search technology. Now, as director of research for Google, the Web's hottest search engine, Henzinger stands at the cutting edge of what many consider the Web's most useful technology.

Her colleagues in the tight-knit field of Web search technology consider Henzinger a pioneer. "Monika was involved in Web search research from the start, even before Google was founded," says Bay-Wei Chang, a senior research scientist at Google. "She comes up with great ideas and then goes off and thinks them through."

Henzinger traces her early interest in maths and science to a magazine article on the Martian atmosphere. "I thought that was the coolest thing in the world," she says. Thereafter, maths and physics teachers gave her problems to work on outside of class. Her career goal at the time? Mission specialist on a space shuttle.

Years later, her feet firmly planted in Silicon Valley, Henzinger turned her attention to Web information retrieval research at the Digital Systems Research Centre in Palo Alto, California. There, she met two Stanford grad students whose research piqued her interest. Instead of ranking Web pages by how many times a key word appears (as other search engines do), they chose to rank them by the popularity and relevance of each page according to the Web's vast link structure. For example, they interpreted a link from page A to page B as a vote by page A for page B. The more votes, the higher the ranking. These two students, Sergey Brin and Larry Page, went on to found Google in 1998, and a year later Henzinger started up the company's research department. Google now processes more than 150 million searches a day, or about 1800 searches a second, in 74 languages in 32 countries. Henzinger's algorithms have a lot to do with that success.

"If you think Google is fast, it's because we have good algorithms," says Henzinger, sitting in a conference room in Google's cramped headquarters. Such good algorithms, in fact, that Yahoo pays Google $US7 million a year to use them and America Online tapped Google to be its exclusive search engine in May 2001. Google prides itself on fairness; companies can't rig the system to come out on top. But people still try to fool the ranking algorithm and some succeed. Henzinger is currently at work on a way to outsmart the hackers. "I'm thinking of an algorithmic way of doing this," Henzinger says. Evidently, first loves die hard.