Powering a Google search

Not long ago, answering a query meant traveling to the reference desk of your local library. Today, search engines enable us to access immense quantities of useful information in an instant, without leaving home. Tools like email, online books and photos, and video chat all increase productivity while decreasing our reliance on car trips, pulp and paper.

But as computers become a bigger part of more people's lives, information technology consumes an increasing amount of energy, and Google takes this impact seriously. That's why we have designed and built the most energy efficient data centers in the world, which means the energy used per Google search is minimal. In fact, in the time it takes to do a Google search, your own personal computer will use more energy than Google uses to answer your query.

Recently, though, others have used much higher estimates, claiming that a typical search uses "half the energy as boiling a kettle of water" and produces 7 grams of CO2. We thought it would be helpful to explain why this number is *many* times too high. Google is fast — a typical search returns results in less than 0.2 seconds. Queries vary in degree of difficulty, but for the average query, the servers it touches each work on it for just a few thousandths of a second. Together with other work performed before your search even starts (such as building the search index) this amounts to 0.0003 kWh of energy per search, or 1 kJ. For comparison, the average adult needs about 8000 kJ a day of energy from food, so a Google search uses just about the same amount of energy that your body burns in ten seconds.

In terms of greenhouse gases, one Google search is equivalent to about 0.2 grams of CO2. The current EU standard for tailpipe emissions calls for 140 grams of CO2 per kilometer driven, but most cars don't reach that level yet. Thus, the average car driven for one kilometer (0.6 miles for those in the U.S.) produces as many greenhouse gases as a thousand Google searches.

We've made great strides to reduce the energy used by our data centers, but we still want clean and affordable sources of electricity for the power that we do use. In 2008 our philanthropic arm, Google.org, invested $45 million in breakthrough clean energy technologies. And last summer, as part of our Renewable Energy Cheaper than Coal initiative (RE), we created an internal engineering group dedicated to exploring clean energy.

We're also working with other members of the IT community to improve efficiency on a broader scale. In 2007 we co-founded the Climate Savers Computing Initiative, a group which champions more efficient computing. This non-profit consortium is committed to cutting the energy consumed by computers in half by 2010 — reducing global CO2 emissions by 54 million tons per year. That's a lot of kettles of tea.

Update on 1/12 @ 4 PM: Harvard professor Alex Wissner-Gross provided new details on his energy research, in a TechNewsWorld article.

Announced by Urs Hölzle, Senior Vice President, Operations

Google international approach to search

In previous posts in this series, you have read about the challenges of building a world-class search engine. Our goal is to make Google’s search be relevant to all people, regardless of their language or country. As my colleague Amit Singhal described, we use statistical data as the basis for making sweeping algorithmic changes. Many of these changes can be rolled out across all languages we support, but in some cases the unique characteristics of each language require some algorithmic considerations and tuning. And to make things really interesting, there are cases where the same language is different across countries. Obvious examples are "color" in the U.S. vs. "colour" in the U.K., or "camião" in Portugal vs. "caminhão" in Brazil.

My name is Daphne Dembo, and my focus is improving Google's international search. This is a tough challenge, since Google search is used in many countries and languages where our engineers have little personal knowledge. Initially, the international search improvements were done by Search Quality engineers who were passionate about their languages and countries: Lina from Sweden improved our parsing of compound words in German and Swedish; Dimitra from Greece introduced diacritical support; Ishai from Israel worked on transliteration corrections for Hebrew and Arabic; Trystan from Australia created methods for identifying local search results and ranking them together with foreign ones from the same language; Alex, a bilingual Ukrainian and Russian, introduced morphological understanding of these languages. As the importance of our international search grew, we solicited help from Googlers in all our offices. Finally, we are leveraging an international network of search specialists who help us understand search within the unique combination of their language and country.

Our first step in providing search support for a language is to train our language model on a large collection of documents in that language. This ensures that our language model is more precise and comprehensive — for example, it incorporates names, idioms, colloquial usage, and newly coined words not often found in static dictionaries. For instance, we recently started identifying Swahili, and used pages such as this one for the Parliament of Tanzania to train our system with the language's nuances. Having a trained language model helps to categorize documents during crawling and indexing of the web and to parse the user's query. Once this stage was complete, we launched Swahili search in countries such as Tanzania and Kenya, enabling local searches for the "Dar es Salaam stock exchange" [Soko la hisa dar es salaam], and "cure for Malaria" [Tiba ya malaria]. (As always, we are using square brackets to denote a search query. For example, you can search for "soccer" in Hamburg, Germany by clicking on [fußball in hamburg]).

We learn some things from our users, so as people start using our search engine, we can improve the way we rank in that language. Here are few examples:

• Spell corrections: We recently launched spell corrections in Estonian. If your Estonian is rusty, and you don't remember how to spell "smoke detector," we can suggest a spell correction for [suitsuantur], leading to better search results.
• Diacritical marks: Many languages have diacritical marks, which alter pronunciation. Our algorithms are built to support them, and even help users who mis-type or completely ignore them. For example, if you're a resident of Quebec, Canada and would like to know the weather forecast in Quebec City, we'll serve good results whether you type with diacritical signs [Météo à Québec] or without [meteo quebec]. Czech users can read the same excellent results for a popular kids' cartoon by searching for [krtecek] and [krteček]. On the other hand, sometimes diacriticals change the meaning of the word and we have to use them correctly. For example, in Thai, [ข้าว] is "rice," with completely different results than [ข่าว], which is "news"; or in Slovakia, results for "child" [dieťa] are different than results for "diet" [diéta].
• Synonyms: A general case of diacritical support is the handling of synonyms in different languages. Korean searches showed that "samsung" can be viewed as a synonym of "삼성", so that when users search for [samsung], they find results which have the company's name in Korean.
• Compounding: Some languages allow compounding, which is the formation of new words by combining together existing words. You can see a nice example in Swedish, where we return documents about a Swedish credit card for both compounded [Visakort] and non-compounded [visa kort] queries.
• Stemming: Google has developed morphological models that can receive compound words as queries, and return pages which contain their stem, possibly as part of a different compound. For example, when searching for cars in Saudi Arabia, you can search for [سيارة] and [سيارات] because both are variants of the same stem, and both return many common results. A Polish user can search for "movie" [film], and get back results that contain other variants of the stem, such as "filmów," "filmu," "filmie," "filmy." A user from Belarus will find results for all word forms of the capital, Minsk [Мінск]: "Мінску," "Мінска," "Мінскага."

In addition to these semantic factors, Google does even more to parse documents and queries. Understanding the details of language usage in a country is important. Notation of acronyms is different across languages: In Hebrew it is double quotes before the last (left-most) character, as in "prime minister" [רה"מ]; in Thai — a dot at the end of the word, as in police station [สน. ]; while in the U.S. — dots after each character, as in [I.B.M.]. Chinese users quote works of art with a "《", as in: [《手机》剧情], and denote dates with a "日", as in: [2006年1月13日].

Beyond the linguistic elements of a language, we consider how people enter a query. For example, some languages that do not have Latin scripts require keyboards with dual alphanumeric keys. The user can switch between language input modes by typing special keystrokes. In case the user forgets to type this sequence, the queries end up being gibberish. You can see correct handling of these mistakes in Arabic ([hgsuv] corrected to [السعر]) and ([حقثسهيثىفهشم ثممثؤفهخىس ] corrected to [presidential elections]), Hebrew ([vdrk, kuyu] corrected to [הגרלת לוטו]), and Cyrillic ([rehc ljkffhf] corrected to [курс доллара]).

Another way of avoiding the inconvenience of switching keyboard modes is by typing the phonetic sounds of the query in Latin characters. Recreating the correct query in the target language isn't trivial, since there might be many possibilities. We can see several such examples in which we suggest the same query in the intended language for Russian ([biskvitnyi rulet] to [бисквитный рулет]), "movies" in Chinese ([dianying] to [电影]), and "Bank of Attica" in Greek [trapeza attikhs] returns good results for "Τράπεζα Αττικής". Users of 8 Indic languages (such as Hindi, Gujarati, Telugu) can type the phonetic sound of the query, and choose the words in Hindi script:


Ease of typing and reading is also influenced by the language used. Since every Chinese word requires several keystrokes on a standard keyboard, we provide category browsing by Images and related searches so that people don't need to type as much. Similarly, we are now launching Google Suggest, or real-time completion of queries, in many languages.

So far I described how we improve the quality of search in a language. However, there is a strong effect of the location of the user, even if it is only approximated to the country, since in many cases local content is more relevant than global information. For example, searching for Spanish Yellow Pages [Páginas Amarillas] will result in several documents of global interest and several local results in Peru, Mexico, and Spain. Similar to that, searching for [Côte d'Or] in France will return results for that region, whereas searches in Belgium will return results about the chocolate maker.

Note that the display of information should conform to the standards in that country, so we display "," as a decimal notation for Croatian users who want to know how many millimeters are in an inch [inč u milimetrima], or for Italian users who are interested in currency exchange rates [50 euro in dollari]. Similarly, temperatures in Norway [Været i Oslo] will be displayed in Celsius, while in the U.S. — in Fahrenheit [weather Boston].

If everything else fails, we provide cross-language translations based upon Google's translation technology described in this blog post. We will translate your query to English, search English documents on the web, and translate the returned results from English back into the original query language. For example, Japanese users who are interested in viewing Halloween illustrations (Halloween is a holiday which originated in Ireland) can search for [ハロウィン イラスト]. You can then request a Japanese translation of the English pages (at the bottom of the page), which will bring up the translation page in the screenshot below. Similarly, Korean users can search for the latest on Harry Potter [해리 포터], and Arabic readers can search for the opening of the Sydney Opera house [افتتاح دار الاوبرا في سيدني]. (Click on the image to see a larger version.)



All in all, Google Search is being actively developed for more than 100 languages, in 150+ countries, with dozens of improvements launched each month. So far I've covered the basics of how international search works, but this is just the surface of all the international work we do. There are many other interesting topics that impact international markets like usability, homepage and results page layout, and connectivity. An understanding of real cultural and human factors is essential to creating a search engine that resonates with the people who use it. (Click on the image to see a larger version.)



(Update: Replaced example in the 4th bullet point.)

Announced by Daphne Dembo, Engineering Director

Google Custom Search Engine (new)

A Custom Search Engine is a tailored search experience, built using Google's core search technology, that prioritizes or restricts search results based on websites and pages you specify. Your Custom Search Engine can be tailored to reflect your point of view or area of expertise. With a Custom Search Engine, you can:
> Apply your website's look and feel to the search results page.
> Provide search refinements within results pages to make it easier for searchers to find the information they're looking for.
> Add sites to your search engine's index as you surf the web.
> Invite friends and trusted users to co-edit and contribute to your search engine.
> Make money from your Custom Search Engine by participating in Google's AdSense program.

Once you've defined your search engine index, Google will give you a simple piece of code for a search box to place on your site or blog. You'll then have the option to choose various customization options to make the look and feel and functionality of your search engine your own.

For Examples

For More Related: Google Custom Search

Google Search Features

Improve Your Search Experience
Doing a search on Google is easy. Simply type one or more search terms (the words or phrase that best describe the information you want to find) into the search box and hit the 'Enter'

Choosing search terms
Choosing the right search terms is the key to finding the information you need.
Start with the obvious – if you're looking for general information on Hawaii, try Hawaii.
But it's often advisable to use multiple search terms; if you're planning a Hawaiian vacation, you'll do better with vacation Hawaii than with either vacation or Hawaii by themselves. And vacation Hawaii golf may produce even better (or, depending on your perspective, worse) results.

Capitalization

Google searches are NOT case sensitive. All letters, regardless of how you type them, will be understood as lower case. For example, searches for george washington, George Washington, and gEoRgE wAsHiNgToN will all return the same results.

Automatic "and" queries
By default, Google only returns pages that include all of your search terms. There is no need to include "and" between terms. Keep in mind that the order in which the terms are typed will affect the search results. To restrict a search further, just include more terms. For example, to plan a vacation to Hawaii, simply type vacation hawaii.

Automatic exclusion of common words

Google ignores common words and characters such as "where" and "how", as well as certain single digits and single letters, because they tend to slow down your search without improving the results.

If a common word is essential to getting the results you want, you can include it by putting a "+" sign in front of it. (Be sure to include a space before the "+" sign.)

Another method for doing this is conducting a phrase search, which simply means putting quotation marks around two or more words. Common words in a phrase search (e.g., "where are you") are included in the search.

For example, to search for Blair Witch Project, Volume I, use:

Or You Search like This:

Negative terms
If your search term has more than one meaning (bass, for example, could refer to fishing or music) you can focus your search by putting a minus sign ("-") in front of words related to the meaning you want to avoid.

For example, here's how you'd find pages about bass-heavy lakes, but not bass-heavy music:

"I'm Feeling Lucky"

After you've entered your search terms, you might want to try the "I'm Feeling Lucky" button, which takes you straight to the most relevant website that Google found for your query. You won't see the search results page at all, but if you did, the "I'm Feeling Lucky" site would be listed on top.

For example, if you're looking for the Stanford University homepage, just enter Stanford and click "I'm Feeling Lucky" instead of the Google Search button. Google will take you directly to "www.stanford.edu."

Related: Advanced Google Search

Related: Help and other Google Search Features