Since 2001, Google has acquired many companies, mainly focusing on small venture capital companies. In 2004, Google acquired Keyhole, Inc..[71]

The start-up company developed a product called Earth Viewer that gave a 3-D view of the Earth. Google renamed the service to Google Earth in 2005. Two years later, Google bought the online video site YouTube for $1.65 billion in stock.[72]

On April 13, 2007, Google reached an agreement to acquire DoubleClick for $3.1 billion, giving Google valuable relationships that DoubleClick had with Web publishers and advertising agencies.[73] Later that same year, Google purchased GrandCentral for $50 million.[74] 

The site would later be changed over to Google Voice. On August 5, 2009, Google bought out its first public company, purchasing video software maker On2 Technologies for $106.5 million.[75] 

Google also acquired Aardvark, a social network search engine, for $50 million. Google commented in their internal blog, "we're looking forward to collaborating to see where we can take it".[76] And, in April 2010, Google announced it had acquired a hardware startup, Agnilux.[77]

In addition to the numerous companies Google has purchased, the company has partnered with other organizations for everything from research to advertising. In 2005, Google partnered with NASA Ames Research Center to build 1,000,000 square feet (93,000 m2) of offices.[78] 

The offices would be used for research projects involving large-scale data management, nanotechnology, distributed computing, and the entrepreneurial space industry. Later that year, Google entered into a partnership with Sun Microsystems in October 2005 to help share and distribute each other's technologies.[79]

The company also partnered with AOL of Time Warner,[80] 

to enhance each other's video search services. Google's 2005 partnerships also included financing the new .mobi top-level domain for mobile devices, along with other companies including Microsoft, Nokia, and Ericsson.[81] 

Google would later launch "Adsense for Mobile", taking advantage of the emerging mobile advertising market.[82] 

Increasing their advertising reach even further, Google and Fox Interactive Media of News Corp. entered into a $900 million agreement to provide search and advertising on popular social networking site MySpace.[83]

In October 2006, Google announced that it had acquired the video-sharing site YouTube for US$1.65 billion in Google stock, and the deal was finalized on November 13, 2006.[84] Google does not provide detailed figures for YouTube's running costs, and YouTube's revenues in 2007 were noted as "not material" in a regulatory filing.[85] In June 2008, a Forbes magazine article projected the 2008 YouTube revenue at US$200 million, noting progress in advertising sales.[86] In 2007, Google began sponsoring NORAD Tracks Santa, a service that pretends to follow Santa Claus' progress on Christmas Eve,[87] using Google Earth to "track Santa" in 3-D for the first time,[88] and displacing former sponsor AOL. Google-owned YouTube gave NORAD Tracks Santa its own channel.[89]

In 2008, Google developed a partnership with GeoEye to launch a satellite providing Google with high-resolution (0.41 m monochrome, 1.65 m color) imagery for Google Earth. The satellite was launched from Vandenberg Air Force Base on September 6, 2008.[90] Google also announced in 2008 that it was hosting an archive of Life Magazine's photographs as part of its latest partnership. Some of the images in the archive were never published in the magazine.[91] The photos were watermarked and originally had copyright notices posted on all photos, regardless of public domain status.[92]

In 2010, Google Energy made its first investment in a renewable-energy project, putting up $38.8 million into two wind farms in North Dakota. The company announced the two locations will generate 169.5 megawatts of power, or enough to supply 55,000 homes. The farms, which were developed by NextEra Energy Resources, will reduce fossil fuel use in the region and return profits. NextEra Energy Resources sold Google a twenty percent stake in the project in order to get funding for project development.[93] Also in 2010, Google purchased Global IP Solutions, a Norway based company that provides web-based teleconferencing and other related services. This acquisition will enable Google to add telephone-style services to its list of products.[94] On May 27, 2010, Google announced it had also closed the acquisition of the mobile ad network, AdMob. This purchase occurred days after the Federal Trade Commission closed its investigation into the purchase.[95] Google acquired the company for an undisclosed amount.[96] In July 2010, Google signed an agreement with an Iowa wind farm to buy 114 megawatts of energy for 20 years.[97]

Source : http://en.wikipedia.org/