This is how Google tries to guess what you want, even if you don't know what you want. If thousands of people search for "shoes with toes" and eventually find their way to Vibram, the shoe company that designs footwear with individual pockets for each toe, the search engine notes the connection. In short, Google's search engine is moving from reactive to predictive. Just a few years ago, the notion of figuring out what a human being wanted even before that same human being figured it out would have been virtually impossible. Google hasn't yet built a computer that can think. But by indexing what billions of people search for, it has, with its search engine, built a near-passable facsimile.
Yet it must get even better. It's not just Facebook and Twitter that represent the next generation of Google's competitors. This year, Apple also jumped into the advertising business, launching an ad platform that runs on the hundreds of thousands of apps for its iPhones and iPads.
"If people want to find out what restaurant to go to, they're not going to their search engine and typing in "Japanese" and "Palo Alto," Apple CEO Steve Jobs said at a recent conference. Instead, he contended, users are turning to specific apps. If that's the case, Google's dominance may become much less relevant to both users and advertisers.
Google knows its survival depends on its ability to perfect the science of reading your mind. Ben Gomes, the 50th person hired at Google and the man who's responsible for the look and feel of the company's website, says the company is clear it must remain one step ahead of its competitors in the battle to deliver perfect search results.
"I've been here 10 and a half years," he says, "and search is still the heart of what we do."
Google still retains the lion's share of the search market in most parts of the world. But a new wave of potential competitors is starting to cut in to that dominance - in large part, because the definition of "search" is becoming much more broad. Here's a look at the competitors, and why they're a threat:
Why: With 400 million users, Facebook has become home to huge stores of content, including photos and video. The site is also a hub for personal information that often can't be found anywhere on the Web.
Importance: High. Facebook's size and, perhaps more importantly, its meteoric growth, make it likely to soon eclipse Google as the world's most-visited site.
Why: The microblogging site has become the go-to source for updates on breaking news, because often the first reports come from everyday people posting updates from their cellphones.
Importance: Medium. While Twitter's real-time model has forced companies such as Google and Facebook to play catch-up, the site's usefulness as a search engine is related mostly to breaking news.
Why: Microsoft's search engine represents the first real shot in years by a major company to challenge Google's core business. Bing caught Google executives off guard, with its focus on consumer services and user experience.
Importance: Medium. Bing still controls a small share of the overall search market. Yahoo has outsourced its search engine duties to Microsoft, and the two entities combined may still pose a threat.
Why: Increasingly, users are turning to search engines to find things to buy. Amazon's huge store of product information makes it a prime spot for consumers. Unlike Google, Amazon also lets users buy the products they search for directly from the same source.
Importance: Low. Even though Amazon may steal some users from Google, anyone who isn't looking to buy something is unlikely to use Amazon as a search engine.