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.
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.”