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Why Google Went Instant

The service, an engineering marvel, could boost Google’s bottom line.
September 20, 2010

Last week, Google rolled out a major change to its search engine’s interface. American users, and some users in other countries, began to see the results for their Google searches appear onscreen while they were still typing. For example, if you type “b” into Google’s search box, you might see the results of a Google search for “bank of america” appear below the box, along with a sponsored link from Bank of America. Keep typing until you have “bat” in the search box, and the results could suddenly change to match a search for “batman.”

Google Instant, as it’s called, is primarily about making searching faster and more effective, according to Google. The company says the service saves two to five seconds per search, and helps users refine their queries by providing instant feedback.

Google doesn’t deny that maintaining its search ad sales was a primary focus in testing the service. The company only gets paid for an advertisement, or sponsored link, when a user clicks on the ad, and ads are targeted to specific searches. By displaying a search’s ads onscreen a couple of seconds sooner, the frequency of users clicking on those ads could only go up.

Google’s search ads are a $20 billion business, thanks to the popularity of its lightweight, minimally intrusive text ads sold against specific searches. So it’s unthinkable that Google would risk its cash cow simply because employees thought instant results were cool.

But are users finding Google Instant useful? Some Internet pundits have been skeptical. One Web developer conducted an eye-tracking user study of seven people chosen to represent a wide age range of heavy Internet users. His test found that none of them were jumping down to the early-arriving results. Instead, they continued typing until they had finished the search query.

Google insists that its own heavy testing says otherwise. Company spokesman Jake Hubert says, “We actually found that people do look at the predictions and the results, but they don’t necessarily notice that’s what they’re doing.” Google is known for extensive testing of even the slightest change to its moneymaking search engine. Other recent products, such as the Google Buzz social network and the Google Wave everything-plus-the-kitchen-sink collaboration tool, didn’t catch on as hoped. But Google Instant isn’t a new product. It’s a presumed enhancement to the most successful product on the Internet.

Google Instant is also an impressive engineering feat. How can Google deliver a nonstop stream of instant results to hundreds of millions of users without melting the Internet? It turns out that the instant results are powered not by high bandwidth, but by advances in Google’s back-end data centers and inside your browser.

Othar Hansson, tech lead for the feature, says that loading search results as you type only uses a few thousand bytes of data for each new set of 10 results and any text-based ads targeted to the search. “The people that manage our traffic barely even blinked when we said we’re going to have this effect on search traffic,” he said in a phone interview, “because we have this other thing called YouTube.” The five to 50 kilobytes of data in a new set of search results, even if they include image thumbnails, are tiny compared to even one second of online video.

The real magic in Google Instant comes largely from advances in data-center hardware in the past 18 months, Hansson said. Faster servers and fatter connections between them are coupled with new tricks for caching the results for the majority of Google searches. Most searches typed by users aren’t very original. So when you type “bat” into Google, it’s statistically almost certain you’re going to keep going and type an additional “man” into the box. Rather than wait for you, Google sends over the results for “batman.”

“We make sure that searches on which we are confident get served fastest,” Hansson said. If your search query doesn’t seem obvious based on other people’s behavior, Google hangs back to see what else you type. In programmer-speak, Google has changed its back end from being “stateless,” which means that if you type five searches in a row, it treats each one as a whole new session, to maintaining a session state that tracks what search results have already been sent to you. That means a lot more computer memory work is going on inside Google’s data centers.

In the end, he said, Google Instant actually reduces the total cost of a search to the company by handing out the cached results for most searches. Separately, Google has updated its Internet crawlers to keep those cached results freshly stocked with the most recent news stories, blog posts, and other content that may be only a few minutes old.

The other big advancement happens inside your browser. Google research found that most people type at a rate which leaves a 300-millisecond gap between keystrokes. The goal for Google Instant, then, became to change the results in less than 300 milliseconds. To do that, engineers embarked on projects to optimize the JavaScript code that runs inside its pages so that search results and ads can be parsed and displayed onscreen in a couple of hundred milliseconds. JavaScript behavior varies a lot from one browser to the next. That meant that each of the four browsers supported by Google Instant–Internet Explorer, Apple’s Safari, Mozilla’s Firefox, and Google’s own Chrome– needed to be customized separately with different JavaScript code.

It’s no coincidence that these browsers’ JavaScript support has also been improved repeatedly in the past couple of years. As commercial websites add more and more interactivity, much of it powered by JavaScript, the performance of JavaScript has come to be the difference between fast and slow browsing most noticed by users oblivious to how the whole thing works. A year ago, a 300-millisecond response time would have probably been impossible. In the latest browsers, it’s become reliable.

Overall, Google claims that 15 separate technology innovations–most of them considered trade secrets–work together to make Google Instant possible.

Search Engine Land editor Danny Sullivan, a respected commentator, thinks that Google Instant could have another important business impact. He suggests it is less about running up more ad traffic and more about making competitors Bing and Yahoo seem slow. “I suspect that mainly, users will feel like Google is just faster,” he wrote in an e-mail. “If many of your queries are already the first thing that Google guesses at, the results are right there for you, immediately.” Asked if Google Instant will change the behavior of Internet users, he replied, “Your behavior is to be happier with Google.”

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