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 searchfeature 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 Searcho 1.1 PageRanko 1.2 Search productso 1.3 Non-indexable datao 1.4 Google optimizationo 1.5 Universal search

2 Functionalityo 2.1 Search syntax

o 2.2 Query expansiono 2.3 "I'm Feeling Lucky"o 2.4 Rich snippetso 2.5 Special featureso 2.6 Search optionso 2.7 Error messages

2.7.1 January 2009 malware bugo 2.8 Google Doodleso 2.9 Google Caffeineo 2.10 Conversational search (OK Google)o 2.11 Hummingbird update

3 Privacyo 3.1 Encrypted searcho 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.