Makani Power

Google previously invested in the green energy startup before it completed its purchase of Makani Power last May. Since then, Makani has operated out of Google's X Labs to build airborne wind turbines, which have the potential to be the dominant form of clean energy. Google currently has a working prototype.

Illustration: Ellis Hamburger

Google's purchase of Zagat in September 2011 was mostly about getting the company's content into Google's various services, including Maps, search, and Earth. With Zagat's treasure trove of ratings and reviews, Google has been better able to compete with services like Yelp.

Screenshot / YouTube

Google has many uses for the New Mexico-based company that made solar-powered flying drones, which was purchased in April. Though it can contribute photos to Google Maps and Earth or even work with the Google X project Makani Power, Titan Aerospace is playing a big role in Google’s Project Loon, which strives to bring internet connectivity to those regions without it by beaming broadband from the sky.

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Last March, Google purchased the three-person startup from Toronto to continue researching its experimental neural network, which basically uses a computer to simulate and mimic the processes of a human brain, but make them more efficient. Google recently released a white paper describing how its neural networks can optimize operations within its many global data centers. Also, in January, Google’s neural network proved it could identify the hundreds of millions of street and house numbers to help its Google Street View users with location and navigation. This neural network, with its massive potential, will hopefully expand in time to improve Google's other services.

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Google wants to organize the world’s data and multimedia, which is why the company acquired DeepMind Technologies in January  — to give computers “corresponding perception capabilities” so machines can do things like “listen to soundtracks and music, and build descriptions of their perceptions.” Thanks to Deepmind, Google is teaching computers how to do things like annotate images and video and be able to describe visual objects. Google cofounders Sergey Brin and Larry Page sat down with VC Vinod Khosla in July to insist “we will be able to make machines that can reason, think and do things better than we can.”

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Boston Dynamics used to make mobile research robots for the Pentagon, but now they’re making robots for Google. The effort is being led by former Android boss Andy Rubin. When this project comes to fruition, it could help the company deliver packages, particularly in urban areas, in a similar fashion to Amazon's proposed delivery drones, according to The New York Times. There are plenty of potential uses for robotics, but for now, Google’s spectacular machines are training with the U.S. Marine Corps.

Waze

Noam Bardin, Waze founder.

Google picked up the GPS and navigation company for about $1 billion last June, even though the company wasn't making much money at the time. Still, with so much crowdsourced data from its 44 million users, Google has been able to vastly improve its real-time mapping data about road conditions, closures, and accidents, as well as data about businesses and services submitted by Waze users.

Nest

In 2011, Google announced a plan to bring Android to the living room — well, at least to use Android to control one's light bulbs — with a project called "Android @Home." Google has since wiped all mentions of that project, but the $3 billion purchase of Nest Labs in January might revitalize an Android platform for the living room. Even if Google doesn't bring back Android @Home, the acquisition still puts the company in an excellent strategic position. Nest's two home products, a thermostat and a smoke detector, both make a lot of sales but also collect a great deal of data about its users' habits. Google loves data, and could potentially leverage that precious user information for its other services like Google Now or Google Maps.

Google dropped more than $3 billion on DoubleClick in March 2008, although the acquisition was announced that previous April. Since then, DoubleClick has been a cash cow for Google, developing and serving its ad services to huge customers like Coca-Cola, Nike, and Apple. Google's advertising arm is enormous: About 95% of Google's reported $12.67 billion in revenue came from advertising in the company's most recent quarter.

YouTube

In exchange for $1.65 billion in stock, Google obtained what was, and still is, the world's biggest video sharing site. It's the number three website in the U.S. and globally, according to Alexa, and Google says users upload 100 hours of new video content every minute. And thanks to its monetization platforms, users are now finding ways to make a living just by posting videos to YouTube. It's a huge part of the internet's culture.

AP

At the time, Andy Rubin's Android was just a 22-month-old startup that made "software for cell phones." Google spent just $50 million on the company, which Google's mergers and acquisitions chief at the time David Lawee called "the best deal ever." Less than a decade after the 2006 purchase, Google's Android is now the most-used smartphone operating system in the world, and the little green robot is Google's mobile presence in everything it touches — first it was smartphones, but now Android is powering tablets, televisions, car systems, video game platforms, and wearable devices for one's wrist and one's face. Android is most certainly Google's most important acquisition.

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