Google is one of the most valuable public companies in the world, after Amazon and Apple. As of January 16, 2020, Google's parent company Alphabet Inc. (NASQAQ: GOOGL) became the fourth company ever to reach a $1 trillion market value. Unlike companies such as Apple's reliance on more singular business lines such as the iPhone to drive revenue, Google has multiple major business lines providing streams of income. Many of Google's revenue sources have experienced tremendous growth over the years.

Google AdWords and Search Advertising

The company's proprietary advertising service, Google AdWords, continues to be a major business line and contributor to Google's revenue at 68%, or $45 billion in 2014. In 2015, Google's aggregate paid clicks, a key advertising measure, rose 31% from the previous year.

Across all industries, companies continue to drive up the cost per click (CPC). In 2011, the insurance industry commanded 24% of Google AdWords revenue, for as much as $54.91 for top keywords, including "auto insurance price quotes" and "life insurance comparison quotes."

However, other industries have even more expensive costs per click. In 2015, "San Antonio car wreck attorney," "Flood restoration Chicago" and "Austin drug rehab" could command as much as $670.44, $346.49 and $463.05, respectively. More and more companies compete to gain the top spot in Google AdWords, further driving up the price of Google's aggregate paid clicks.

Google AdSense Network

Google AdSense is another one of Google's most well-known lines of business. While Google AdWords enables businesses of all sizes to advertise across Google's websites, including Gmail, YouTube and Google's search engine, Google AdSense enables third-party websites to display Google advertising on their pages. The AdSense networks accounted for 21%, or about $14 billion, of Google's total 2014 revenue. Through its AdWords and AdSense advertising products, Google also seeks to continue its dominance on the mobile web.

Google's Other Bets

One of the main challenges of identifying Google's major non-search lines of revenue is the secrecy around those projects. Housed under Google's "moonshot" research and development arm, X Development, projects such as Waymo self-driving cars have sprung out of X. In 2015, revenue from those projects rose to $448 million, up from $327 million in 2014. However, Google's other projects had operating losses of $3.56 billion, up from $1.9 billion in 2014. During its Feb. 1, 2016, earnings call, Alphabet and Google CFO Ruth Porat indicated the most profitable of Google's other projects are Fiber, Nest and Verily.

Google Fiber

First announced in 2010, Google Fiber is a broadband service offering high-speed gigabit internet and TV at rates up to 1000 mbps. Currently, Google Fiber is available and operating in 18 cities, including Kansas City, Missouri; Provo, Utah; and Austin, Texas. At the time during the 2015 Q4 conference call, Porat indicated Fiber was the most costly project out of all of Google's other projects.

Google's Fiber Phone, which operates as both a home and mobile phone, can also be added onto a phone plan.

Google Nest

The Nest Learning Thermostat was one of the first Internet of Things products for homes to gain a widespread audience. On Jan. 14, 2014, Google acquired startup Nest Labs, a home service of smart interconnected thermostats and smoke detectors, for $3.2 billion. At the time of acquisition, Nest Founder and CEO Tony Fadell claimed to have sold around 1 million thermostats. Under Google, Nest continues to focus on thermometers and other smart home technologies.

Verily Life Sciences

Formerly known as Google Life Sciences, Verily focuses on a wide range of life science and human health projects, including a bandage-sized glucose monitor and a perfect "baseline" of human health. Verily is focused on finding solutions to diseases and other global health problems, including smart contact lenses, assistive eating devices for people with hand disabilities, and other healthcare challenges.

The Bottom Line

Fueled by the high profitability of its AdWords and AdSense products, Google stands as one of the five most valuable companies in the world. From 2011 to 2015, Google provided an annual return of 21.2% to its investors. Despite some investors' perspectives that Google's other projects are driving down the profitability of the company, its diversification of major business lines continues to take the company to reach new financial milestones.