By any measure, Google is a remarkably successful company. In just over 15 years, it's created one of the world's most valuable franchises from what is often described as the greatest single product on the Internet: search.
The fortunes generated by the eponymous search engine have financed a market-leading mobile operating system called Android, opened up the cloud to thousands of small businesses, helped fund cutting-edge projects like the self-driving car and Google Glass, and pushed the company into alternative energy, where it's now a major investor.
Additionally, Google has created a culture and workplace that's the envy (and sometimes punch line) of Silicon Valley.
With such triumphs inevitably comes scrutiny, and Google is the recipient of plenty. CNBC.com has been reporting on how the company's unexpected changes to its search algorithm can punish small Websites and leave them scratching and clawing to recover.
Outrage surrounding those practices presents just one vulnerability the search giant faces as it seeks to protect its turf and expand its dominance. There are plenty of other concerns, for despite all its investments into new areas, online advertising still accounts for 90 percent of revenue. Here are five risks Google faces over the next 10 years:
Sure, Google is investing massively in Google Plus as its answer to the social networking goliath Facebook, and by tying everything to your Gmail credentials, Google has a formidable way to keep users on its services. But as far as parents sharing kid pics with their friends, college students checking out what classmates are up to and people just generally killing time, Facebook is the place to go.
Nor does Google have anything to really take on LinkedIn in professional networking or Twitter in microblogging. In the battle for consumer eyeballs and engagement, that's significant ground the search giant is ceding to younger and nimbler Internet companies.
Google has spent a decade trying to gain relevance in social, going back to its Orkut network in 2004 and including products like Buzz and Friend Connect. If not for a dogged Harvard dropout turning down massive takeover offers well before he was pulling in much revenue, the world could look very different for Google. As is, this is an uphill battle.
According to eMarketer, Facebook controls 68 percent of the $16 billion in ad spending on U.S. social networks this year, followed by Twitter at 7 percent and LinkedIn at less than 5 percent. Google falls somewhere in the "other" category.
And it's notable that the top evangelist for Google Plus and one of the company's most outspoken executives, Vic Gundotra, left the company in April.
(Scroll through an interactive timeline of Google's post-IPO history, below)
2. Vertical search
On the desktop, Google is the most popular front door to the Internet. It's how people quickly find what they're looking for, and it's a cash cow for Google. Big companies spend hundreds of millions—sometimes billions—of dollars on sponsored links that run alongside search results to make sure they're getting Web traffic.
The mobile world is very different. Smartphone users tend not to go to Google.com to search for hotels, clothes or gifts. They go to particular apps, meaning there is no central front door to the mobile Web. While Google remains at the middle of mobile computing with Android and popular apps like Maps, YouTube and Gmail, it doesn't control the discovery experience.
Travelers looking for a place to stay can go to apps from HotelTonight, Airbnb, Priceline or any number of hotel-specific apps (Google recently licensed software from mobile hotel search provider Room 77 as a nod to the importance of accommodations). For shopping, Amazon.com, eBay, Walmart and Groupon all have popular mobile apps, and for entertainment there's Netflix and Hulu, among others.
Whatever the category, if consumers are beginning their search outside of Google, then Google isn't getting paid for helping them find what they're looking for. And more and more activity is happening off desktops and moving to phones and tablets.
Google is plenty aware. This comes directly from the risks section of its annual report: "search queries are increasingly being undertaken via 'apps' tailored to particular devices or social media platforms, which could affect our share of the search market over time."
Google has improved its voice-activated search technology to let people on the go search for anything, whether it's a friend's contact information or the best app for finding a weather report. And the company is the market leader in mobile advertising, thanks in large part to its purchase of ad network AdMob in 2009.
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There's no question that Google is positioned for a long-term run in smartphones and mobile apps, but can it transfer its dominant market share in desktop search to the far more disparate mobile economy?
Google's $390 billion stock market value is built on dominance, not just relevance.
3. Payments and commerce
Remember NFC? Google does, though it would rather not. Short for near-field communication, the technology was central to Google's costly effort at getting new payment terminals into retailers' hands, so that consumers could pay with a chip attached to their phone.
It was one of many failed attempts that Google has made in the payments market, where PayPal, Apple and Amazon have had far more success getting customers to buy stuff with a couple clicks.
It's not just the $1.5 trillion e-commerce market that Google is trying to play in. It's all the extraordinarily valuable data that comes from knowing what, when and how people make purchases. Just ask Amazon or Netflix about the power and effectiveness of their recommendation engines.
Again, there's no sitting still in Mountain View. Google Wallet, its payments product, remains a priority, and the company has made it far easier of late for Android users to make purchases—food delivery, music, games, etc.—with their Google credentials.
That just means it's meeting minimum expectations. Google has to do more to be at the center of how we spend throughout the day, everyday. With the IPO of Chinese e-commerce leader Alibaba on the horizon, competition is only poised to increase.
4. Slowing growth
This is just the law of big numbers, but it can't be ignored. Google's revenue growth, excluding the Motorola business, slowed to 21 percent in 2013 from 29 percent two years earlier and close to 100 percent the year after its IPO.
At more than $50 billion in annual sales, Google's growth rate is still mighty impressive relative to its peers of that size. Google continues to act like a growth company. Along with Amazon, it's the only U.S. tech company among the eight with revenue of at least $40 billion that doesn't pay a dividend.
That means investors trust that Google can put its $60 billion in cash to work in ways that are more effective than returning some of it to shareholders. Without the additional, and to date elusive, revenue stream, investors will get antsy. They always do. Just look at Apple, which has bowed to pressure from Carl Icahn to bolster its payments to investors.
Companies of a certain size inevitably mature. The investor base changes as does the workforce. Top talent leaves to chase the next big thing or even hit the beach. Google's business, to stay truly cutting edge, needs the best engineers to keep flying through the doors and needs shareholders to stay patient. Everyone else should stay tuned.
Regulators, both at home and abroad, are watching Google's every move. When the company agreed to acquire flight information provider ITA in 2010, it took almost a year for the Justice Department to clear the deal amid concern that Google would favor its own travel listings in search results.
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Yelp has criticized Google for giving preferential treatment to reviews of restaurants and local businesses on its own service. The European Commission has spent almost four years investigating antitrust-related complaints against the company.
Google controls one-third of the global digital ad market and more than 40 percent of the U.S. market, according to eMarketer. In its core online ad business, any increase to its share—certainly via acquisition—will be rigidly scrutinized. So Google is faced with a need-to-grow-but-can't-grow conundrum.
That's a big reason Google has been spending big elsewhere, acquiring connected thermostat maker Nest Labs for $3.2 billion and mapping software provider Waze for close to $1 billion.
That's after 10 years as a public company. How much more will Google know at the 20th anniversary of its IPO?
—By CNBC's Ari Levy. Follow him on Twitter