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Google Search
Logo Google 2013 Official.svg
Screenshot [show]
Web address www.google.com (US)
Commercial? Yes
Type of site
Web search engine
Registration Optional
Available in 123 languages
Written in Python, C, C++[1]
Owner Google
Launched September 15, 1997[2]
Revenue From AdWords
Alexa rank
Steady 1 (April 2015)[3]
Current status Active
Google Search, commonly referred to as Google Web Search or just Google, is a web search engine owned by Google Inc. It is the most-used search engine on the World Wide Web,[4] handling more than three billion searches each day.[5][6] As of February 2015 it is the most used search engine in the US with 64.5% market share.[7]

The order of search on Google's search-results pages is based, in part, on a priority rank called a "PageRank". Google Search provides many different options for customized search, using Boolean operators such as: exclusion ("-xx"), alternatives ("xx OR yy OR zz"), and wildcards ("Winston * Churchill" returns "Winston Churchill", "Winston Spencer Churchill", etc.)[8] The same and other options can be specified in a different way on an Advanced Search page.

The main purpose of Google Search is to hunt for text in publicly accessible documents offered by web servers, as opposed to other data, such as images or data contained in databases. It was originally developed by Larry Page and Sergey Brin in 1997.[9] Google Search provides several features beyond searching for words.[10] These include synonyms, weather forecasts, time zones, stock quotes, maps, earthquake data, movie showtimes, airports, home listings, and sports scores. There are special features for numbers, dates, and some specific forms, including ranges,[11] prices, temperatures, money and measurement unit conversions, calculations, package tracking, patents, area codes,[10] and language translation. In June 2011 Google introduced "Google Voice Search" to search for spoken, rather than typed, words.[12] In May 2012 Google introduced a Knowledge Graph semantic search feature in the U.S.

Analysis of the frequency of search terms may indicate economic, social and health trends.[13] Data about the frequency of use of search terms on Google have been shown to correlate with flu outbreaks and unemployment levels, and provide the information faster than traditional reporting methods and surveys.

Competitors of Google include Baidu and Soso.com in China; Naver.com and Daum Communications in South Korea; Yandex in Russia; Seznam.cz in the Czech Republic; Yahoo! in Japan, Taiwan and the US, as well as Bing and DuckDuckGo.[14] Some smaller search engines offer facilities not available with Google, e.g. not storing any private or tracking information; one such search engine is Ixquick.

Contents [hide]
1 Search
1.1 PageRank
1.2 Search products
1.3 Non-indexable data
1.4 Google optimization
1.5 Universal search
2 Functionality
2.1 Search syntax
2.2 Query expansion
2.3 "I'm Feeling Lucky"
2.4 Rich snippets
2.5 Special features
2.6 Search options
2.7 Error messages
2.7.1 January 2009 malware bug
2.8 Google Doodles
2.9 Google Caffeine
2.10 Conversational search (OK Google)
2.11 Hummingbird update
3 Privacy
3.1 Encrypted search
3.2 FTC Fines
4 Instant Search
5 Redesign
6 Mobile app
7 International
8 Search products
9 Energy consumption
10 Possible misuse of search results
11 See also
12 References
13 Further reading
14 External links
Search[edit]
PageRank[edit]
Main article: PageRank
Google's rise to success was in large part due to a patented algorithm called PageRank that helps rank web pages that match a given search string.[15] When Google was a Stanford research project, it was nicknamed BackRub because the technology checks backlinks to determine a site's importance. Previous keyword-based methods of ranking search results, used by many search engines that were once more popular than Google, would rank pages by how often the search terms occurred in the page, or how strongly associated the search terms were within each resulting page. The PageRank algorithm instead analyzes human-generated links assuming that web pages linked from many important pages are themselves likely to be important. The algorithm computes a recursive score for pages, based on the weighted sum of the PageRanks of the pages linking to them. PageRank is thought to correlate well with human concepts of importance. In addition to PageRank, Google, over the years, has added many other secret criteria for determining the ranking of pages on result lists, reported to be over 250 different indicators,[16][17] the specifics of which are kept secret to keep spammers at bay and help Google maintain an edge over its competitors globally.

In a potential hint of Google's future direction for their Search algorithm, Eric Schmidt, Google's then chief executive, said in a 2007 interview with the Financial Times: "The goal is to enable Google users to be able to ask the question such as 'What shall I do tomorrow?' and 'What job shall I take?'".[18] Schmidt reaffirmed this during a 2010 interview with the Wall Street Journal: "I actually think most people don't want Google to answer their questions, they want Google to tell them what they should be doing next."[19]

In 2013 the European Commission found that Google Search favored Google's own products, instead of offering consumers the best result for their needs.[20] In February 2015 Google announced a major change to its mobile search algorithm which would favor mobile friendly over other websites. Nearly 60% of Google's online search traffic comes from mobile phones. Google wants its users to have access to premium quality websites. Those websites which lack a mobile friendly interface would be demoted and it is expected that this update will cause a massive shake-up of ranks. Business who fail to update their websites accordingly could see a massive dip in their regular websites traffic.[21]

Search products[edit]
The exact percentage of the total of web pages that Google indexes is not known, as it is very difficult to accurately calculate. Google presents a two-line summary and also a preview of each search result, which includes a link to a cached (stored), usually older version of the page.

Google's cache link in its search results provides a way of retrieving information from websites that have recently gone down and a way of retrieving data more quickly than by clicking the direct link. This feature is still available, but many users are not aware of this because it has been moved to the previews of the search results presented next to these.[22][23]

Google not only indexes and caches web pages, but also takes "snapshots" of other file types, which include PDF, Word documents, Excel spreadsheets, Flash SWF, plain text files, and so on.[24] Except in the case of text and SWF files, the cached version is a conversion to (X)HTML, allowing those without the corresponding viewer application to read the file. Users can customize the search engine, by setting a default language, using the "SafeSearch" filtering technology and set the number of results shown on each page. Google has been criticized for placing long-term cookies on users' machines to store these preferences, a tactic which also enables them to track a user's search terms and retain the data for more than a year.[citation needed] For any query, up to the first 1000 results can be shown with a maximum of 100 displayed per page. The ability to specify the number of results is available only if "Instant Search" is not enabled. If "Instant Search" is enabled, only 10 results are displayed, regardless of this setting.[original research?]

In 2012, Google changed its rankings to demote sites that had been accused of piracy, except the Google-owned YouTube site.[25]

Non-indexable data[edit]
Despite its immense index, there is also a considerable amount of data available in online databases which are accessible by means of queries but not by links. This so-called invisible or deep Web is minimally covered by Google and other search engines.[26] The deep Web contains library catalogs, official legislative documents of governments, phone books, and other content which is dynamically prepared to respond to a query.

Google optimization[edit]
Main article: Search engine optimization
Because Google is the most popular search engine, many webmasters have become eager to influence their website's Google rankings. An industry of consultants has arisen to help websites increase their rankings on Google and on other search engines. This field, called search engine optimization, attempts to discern patterns in search engine listings, and then develop a methodology for improving rankings to draw more searchers to their client's sites. Search engine optimization encompasses both "on page" factors (like body copy, title elements, H1 heading elements and image alt attribute values) and Off Page Optimization factors (like anchor text and PageRank). The general idea is to affect Google's relevance algorithm by incorporating the keywords being targeted in various places "on page", in particular the title element and the body copy (note: the higher up in the page, presumably the better its keyword prominence and thus the ranking). Too many occurrences of the keyword, however, cause the page to look suspect to Google's spam checking algorithms. Google has published guidelines for website owners who would like to raise their rankings when using legitimate optimization consultants.[27] It has been hypothesized, and, allegedly, is the opinion of the owner of one business about which there have been numerous complaints, that negative publicity, for example, numerous consumer complaints, may serve as well to elevate page rank on Google Search as favorable comments.[28] The particular problem addressed in The New York Times article, which involved DecorMyEyes, was addressed shortly thereafter by an undisclosed fix in the Google algorithm. According to Google, it was not the frequently published consumer complaints about DecorMyEyes which resulted in the high ranking but mentions on news websites of events which affected the firm such as legal actions against it. Google Webmaster Tools helps to check for websites that use duplicate or copyright content.[29]

Universal search[edit]
Universal search was launched by Google on May 16, 2007. It was an idea which merged the results from different searches into one. Prior to Universal search, a standard Google search would consist of links to different websites. Universal search incorporates a wide variety of information such as websites, news, pictures, maps, blogs, videos, and more to display as search results. Marissa Mayer, VP of Search Products & User Experience during Universal search launch, described the goal of universal search, "With Universal search, we're attempting to break down the walls that traditionally separated our various search properties and integrate the vast amounts of information available into one simple set of search results… We want to help you find the very best answer, even if you don't know where to look."[30]

Functionality[edit]

A definition link is provided for many search terms.
Google search consists of a series of localized websites. The largest of those, the google.com site, is the top most-visited website in the world.[31] Some of its features include a definition link for most searches including dictionary words, the number of results you got on your search, links to other searches (e.g. for words that Google believes to be misspelled, it provides a link to the search results using its proposed spelling), and many more.

Search syntax[edit]
Google's search engine normally accepts queries as a simple text, and breaks up the user's text into a sequence of search terms, which will usually be words that are to occur in the results, but one can also use Boolean operators, such as: quotations marks (") for a phrase, a prefix such as "+", "-" for qualified terms (no longer valid, the '+' was removed from Google on October 19, 2011),[32] or one of several advanced operators, such as "site:". The webpages of "Google Search Basics"[33] describe each of these additional queries and options (see below: Search options). Google's Advanced Search web form gives several additional fields which may be used to qualify searches by such criteria as date of first retrieval.

Query expansion[edit]
Google applies query expansion to the submitted search query, transforming it into the query that will actually be used to retrieve results. As with page ranking, the exact details of the algorithm Google uses are deliberately obscure, but certainly the following transformations are among those that occur:

Term reordering: in information retrieval this is a standard technique to reduce the work involved in retrieving results. This transformation is invisible to the user, since the results ordering uses the original query order to determine relevance.
Stemming is used to increase search quality by keeping small syntactic variants of search terms.[34]
There is a limited facility to fix possible misspellings in queries.
"I'm Feeling Lucky"[edit]
"I'm Feeling Lucky" redirects here. For the 2011 book by Douglas Edwards, see I'm Feeling Lucky (book).
Google's homepage includes a button labeled "I'm Feeling Lucky". Prior to a change[35] in 2012, when a user typed in a search and clicked on the button the user would be taken directly to the first search result, bypassing the search engine results page. The idea was that if a user is "feeling lucky", the search engine would return the perfect match the first time without having to page through the search results. According to a study by Tom Chavez of "Rapt", this feature cost Google $110 million a year as 1% of all searches use this feature and bypass all advertising.[36]

With the introduction of Google Instant, the functionality of the button behaves differently.[37] Currently, the "I'm Feeling Lucky" button changes based on your settings and what webpage you are at. If Google Instant is turned off, the button will direct to the Google Doodles gallery. If Google Instant is turned on and a user hovers over the button, the button text will spin and land on a phrase that starts with "I'm feeling" (e.g. "I'm feeling hungry" or "I'm feeling smart"). Each phrase links to a Google service related to the associated phrase.

Google Chrome and Mozilla Firefox used Lucky Search as the default search string when the user entered a query in the location bar; this functionality was deprecated in later versions.

Rich snippets[edit]
See also: Google Searchology § Rich Snippet
On May 12, 2009, Google announced that they would be parsing the hCard, hReview, and hProduct microformats and using them to populate search result pages with what they called "Rich Snippets".[38]

Special features[edit]
Besides the main search-engine feature of searching for text, Google Search has more than 22 "special features" (activated by entering any of dozens of trigger words) when searching:[10][11][39]

weather – The weather conditions, temperature, wind, humidity, and forecast,[10] for many cities, can be viewed by typing "weather" along with a city for larger cities or city and state, U.S. zip code, or city and country for smaller cities (such as: weather Lawrence, Kansas; weather Paris; weather Bremen, Germany). stock quotes – The market data[10] for a specific company or fund can be viewed, by typing the ticker symbol (or include "stock"), such as: CSCO; MSFT; IBM stock; F stock (lists Ford Motor Co.); or AIVSX (fund). Results show inter-day changes, or 5-year graph, etc. This does not work for many stock names which are one letter long, such as Macy's (M), or are common words, such as Diamond Offshore (DO) or Majesco (COOL). time – The current time in many cities (worldwide),[10] can be viewed by typing "time" and the name of the city (such as: time Cairo; time Pratt, KS). timer – set a countdown[40] sports scores – The scores and schedules, for sports teams,[10] can be displayed by typing the team name or league name into the search box. unit conversion – Measurements can be converted,[10] by entering each phrase, such as: 10.5 cm in inches; or 90 km in miles currency conversion – A money or currency converter can be selected,[10] by typing the names or currency codes (listed by ISO 4217): 6789 Euro in USD; 150 GBP in USD; 5000 Yen in USD; 5000 Yuan in lira (the U.S. dollar can be USD or "US$" or "$", while Canadian is CAD, etc.). calculation results can be determined,[10] as it is calculated live, by entering a formula in numbers or words, such as: 6*77 +pi +sqrt(e^3)/888 plus 0.45. Search results for the formula are displayed after the calculation result. The caret "^" raises a number to an exponent power, and percentages are allowed ("40% of 300").[11] Following the convention used in discrete mathematics, Google's calculator evaluates 0^0 to 1.[41] The calculator also uses the unit and currency conversion functions to allow unit-aware calculations. For example, "(3 EUR/liter) / (40 miles/gallon) in USD / mile" calculates the dollar cost per mile for a 40 mpg car with gas costing 3 euros a liter. The calculator also can calculate digital storage arithmetic (the calculation of bytes). For example, putting in 400MB + 489MB + 1.5GB yields the result 2425MB, or 2.37GB. This is useful since bytes are binary (power of 2), and not decimal as regular numbers are (power of 10). Caveat: it doesn't offer arbitrary precision and is subject to floating point errors in queries like 4,000,000,000,000,000 - 3,999,999,999,999,999.[42] numeric ranges – A set of numbers can be matched by using a double-dot between range numbers (70..73 or 90..100) to match any positive number in the range, inclusive.[11] Negative numbers are treated as using exclusion-dash to not match the number. dictionary lookup – A definition for a word or phrase can be found,[10] by entering "define" followed by a colon and the word(s) to look up (such as, "define:philosophy") maps – Some related maps can be displayed,[10] by typing in the name or U.S. ZIP code of a location and the word "map" (such as: New York map; Kansas map; or Paris map). movie showtimes – Reviews or film showtimes can be listed for any movies playing nearby,[10] by typing "movies" or the name of any current film into the search box. If a specific location was saved on a previous search, the top search result will display showtimes for nearby theaters for that movie. public data – Trends for population (or unemployment rates)[10] can be found for U.S. states and counties, by typing "population" or "unemployment rate" followed by a state or county name. real estate and housing – Home listings in a given area can be displayed,[10] using the trigger words "housing", "home", or "real estate" followed by the name of a city or U.S. zip code. travel data/airports – The flight status for arriving or departing U.S. flights can be displayed,[10] by typing in the name of the airline and the flight number into the search box (such as: American airlines 18). Delays at a specific airport can also be viewed (by typing the name of the city or three-letter airport code plus word "airport"). package tracking – Package mail can be tracked[10] by typing the tracking number of a Royal Mail, UPS, FedEx or USPS package directly into the search box. Results will include quick links to track the status of each shipment. patent numbers – U.S. patents can be searched[10][39] by entering the word "patent" followed by the patent number into the search box (such as: Patent 5123123). area code – The geographical location (for any U.S. telephone area code)[10] can be displayed by typing a three-digit area code (such as: 650). synonym search – A search can match words similar to those specified,[10] by placing the tilde sign (~) immediately in front of a search term, such as: ~fast food.
Six degrees of Kevin Bacon - A search to find the shortest path between an arbitrary actor and veteran Hollywood character actor Kevin Bacon. Simply search using 'bacon number actorname'.
Google Goggles - using the google goggles app on your smartphone you can take a photograph of anything and get quick results for your search. If you wish to pursue more detailed search results you can click the "full results" tab and get a full blown google search of the object you photographed.
Knowledge graph - A search for things, people or places that Google knows about, such as landmarks, celebrities, cities, sports teams, buildings, geographical features, movies, celestial objects, works of art and more, and information that applies to the search term is shown in the upper right. It is rooted in public information such as Wikipedia, United States Census Bureau and the CIA World Factbook.[43]