Because it would be tough to describe all of the technology we’ve built for our many products and services in just one page, here’s a glimpse of some key technologies and technical principles behind our products.
Co-founder Larry Page once described the “perfect search engine” as something that “understands exactly what you mean and gives you back exactly what you want.” We can’t claim that Google delivers on that vision 100 percent today, but we’re always working on new technologies aimed at bringing all of Google closer to that ideal.
Before you even enter your query in the search box, Google is continuously traversing the web in real time with software programs called crawlers, or “Googlebots”. A crawler visits a page, copies the content and follows the links from that page to the pages linked to it, repeating this process over and over until it has crawled billions of pages on the web.
Next Google processes these pages and creates an index, much like the index in the back of a book. If you think of the web as a massive book, then Google‘s index is a list of all the words on those pages and where they‘re located, as well as information about the links from those pages, and so on. The index is parceled into manageable sections and stored across a large network of computers around the world.
When you type a query into the Google search box, your query is sent to Google machines and compared with all the documents stored in our index to identify the most relevant matches. In a split second, our system prepares a list of the most relevant pages and also determines the relevant sections and bits of text, images, videos and more. What you get is a list of search results with relevant information excerpted in “snippets” (short text summary) beneath each result.
As Larry said long ago, we want to give you back “exactly what you want.”
Describing the basic crawling, indexing and serving processes of a search engine is just part of the story. The other key ingredients of Google search are:
Relevance. As Larry said long ago, we want to give you back “exactly what you want.” When Google was founded, one key innovation was PageRank, a technology that determined the “importance” of a webpage by looking at what other pages link to it, as well as other data. Today we use more than 200 signals, including PageRank, to order websites, and we update these algorithms on a weekly basis. For example, we offer personalized search results based on your web history and location.
Comprehensiveness. Google launched in 1998 with just 25 million pages, which even then was a small fraction of the web. Today we index billions and billions of webpages, and our index is roughly 100 million gigabytes. We continue investing to expand the comprehensiveness of our services. In 2007 we introduced Universal Search, which made search more comprehensive by integrating images, videos, news, books and more into our main search results.
Freshness. In the early days, Googlebots crawled the web every three or four months, which meant that the information you found on Google typically was out of date. Today we’re continually crawling the web ensuring that you can find the latest news, blogs and status updates minutes or even seconds after they’re posted. With Realtime Search, we’re able to serve up breaking topics from a comprehensive set of sources just moments after events occur.
Speed. Our average query response time is roughly one-fourth of a second. In comparison, the average blink of an eye is one-tenth of a second. Speed is a major search priority, which is why in general we don’t turn on new features if they will slow our services down. Instead, search engineers are always working not just on new features, but ways to make search even faster. In addition to smart coding, on the back end we’ve developed distributed computing systems around that globe that ensure you get fast response times. With technologies like autocomplete and Google Instant, we help you find the search terms and results you’re looking for before you’re even finished typing.
Online advertising has come a long way since the first banner ads appeared on the web. In the last 15 years, online advertising has evolved more than any other form of traditional advertising as the Internet and its users evolved—including keyword search advertising, rich media display ads and streaming video ads. While Google’s advertising programs have evolved with the industry, we stay committed to providing ads that are so useful and relevant that they serve as a form of information on their own.
With AdWords, for example, advertisers select words and phrases that are relevant to their business as keywords. When people use Google to search for keywords, relevant ads may be displayed alongside the search results. We use an auction to price these ads, which runs automatically every time a user enters a query. Advertisers pay only when a user clicks on their ad, and our system guarantees that they pay the minimum amount necessary to maintain their ad position. They can also immediately track the results of their campaigns.
We give marketers constant feedback so they no longer have to guess how their campaigns are performing or what consumers want. This feedback comes directly from visitors, anonymously and in aggregate, who vote with their clicks on what they‘re looking for and whether they‘re satisfied. With Google Analytics, advertisers get sophisticated aggregate measurements of how visitors arrive to their website, what they do when they‘re there, whether they make a purchase or sign up, and where they go when they‘re done. This data enables marketers to experiment and improve their campaigns continuously: They can try different keywords and ad text, track the value of their keywords and test different layouts of their landing pages to present consumers with relevant information and a high-quality experience. With these insights into customer behavior and customer trends, advertisers can optimise the path from search to sale, so that they reach and satisfy their customers, reach new audiences and improve value on their spend. And in tough economic climates, when value matters more than ever, our measurement tools can help marketers allot their spend to the initiatives that have proven to be most effective.
We’re putting similar technology to work with display ads and other ad formats. In this area, our goal is to build tools that simplify the process of buying and selling ads, make it more effective and measurable, and open the ecosystem to more players. For example, the Google Display Network has grown from simple text ads to include a range of formats including rich media, video, image and Flash, and enables advertisers to reach users across over a million partner AdSense and DoubleClick Ad Exchange websites, and Google properties like Google Finance and YouTube. We automatically match ads to publishers’ webpages in a variety of ways, including by matching ads to the content of the page. As with AdWords, an automatic process determines which ads show up where and how much each advertiser pays.
We’ve also built tools like the DoubleClick Ad Exchange, a first-of-its-kind real-time auction marketplace for display ad space. The Ad Exchange brings together major ad networks, agency trading desks and large publishers. It enables advertisers to bid for ad space in real-time on an impression-by-impression basis, so they can deliver the right display ad at the right time at the right price. And using technology called “dynamic allocation,” it enables publishers to maximise their revenue across both ad space sold directly through their sales force and ad space sold indirectly through ad networks, impression by impression. Across billions of impressions, this can mean significantly increased returns for online publishers.
In the past, the computer applications that people used to connect, communicate and collaborate with others—like email, word processing, calendars and spreadsheets—would have to be “installed” on your computer. This software would live on your computer, jamming it up with old files and outdated versions of the same software. If you spilled coffee on your computer, your files were done for. And you’d continually have to upgrade your programs manually whenever a new version came on the market. These are the kinds of problems that cloud computing technology avoids altogether.
With cloud computing, the apps themselves live “in the cloud”: on the web, so you don’t need any special software or hardware to use them as long as you have an Internet connection. As a result, you can access your stuff from anywhere, using any device with a browser: smartphones, netbooks, laptops. You don’t need to worry about whether an app is compatible with your computer or about upgrades and downloads. Your files are safe from any hard-drive-meets-coffee-cup disaster, and you can invite anyone to share your files or keep them private. If you’re collaborating on something, each of you can work in the same document, without having to save, attach and email version after version, risking the loss of important updates.
For individuals, this can make everyday tasks easier and faster: Imagine planning a wedding, and being able to access your guest list, budget and other important information at work as well as at home, and being able to share everything with your fiancee and family to get input and share planning tasks. For businesses both large and small, cloud computing saves money by removing the need to purchase and maintain software for each client machine, while at the same time enabling employees to be more productive.
This is all possible because the applications and the data associated with them is stored on Google’s machines, rather than on your desktop hard drive or on servers maintained by your company. We keep live copies of your data on multiple servers in each of multiple locations, meaning that there’s no scheduled downtime and your data is backed up and secure.
Mobile and Android
Mobile devices are fast becoming the world‘s portal to information, and we’re committed to developing our products so they can be used on these small computing devices. For many, a mobile phone is the primary or even the only means of accessing the web, so designing our products to be accessible on mobile devices is a key part of making information available to more people around the world. Our goal is to build mobile applications, such as Google Maps and Gmail, that work across multiple devices and locations.
Android is a free, open source mobile platform that any developer can use and any handset manufacturer can install. By opening up mobile devices to all developers, we believe we can drive greater innovation and more choice for the benefit of mobile users everywhere.
We introduced Google Chrome in September 2008 because we believed that a modern browser, designed to handle today’s complex, dynamic web, would be better for users and would help spur greater innovation. We built Google Chrome based on three ideas: speed, simplicity and security.
We built Google Chrome based on three ideas: speed, simplicity and security.
Finally, with Chrome as a foundation we’re building Google Chrome OS, an operating system for a new generation of devices that will share Chrome’s focus on speed, simplicity and security.
We’re always looking for the next great innovation, the next way to make something you never thought could be better or easier to use… better and easier to use. Sometimes our work will result in a tiny improvement you may not notice, like a new way of displaying some part of a search result. Other times, we tear up all we‘ve learned in order to start from the beginning.
Sometimes we combine a few technologies to make them even more useful. Google Translate, for example, is the largest machine translation engine in the world, with more than 50 language pairs; using voice recognition, the mobile version of Google Translate can transcribe your voice, translate what you’ve said into another language, and then speak it back to you in another language. This is just one example of the things that are becoming increasingly possible. And we’re always looking ahead for more.