For innovation both fundamental and practical, it's hard to imagine a greater powerhouse than Google. Jeff Dean, a senior fellow at Google, on Tuesday offered up a very long blog post detailing the company's research achievements in 2018. It is a tour de force, and if you haven't read it, you should definitely do so. You'll be amazed at the breadth of work that goes on at the company.

Google dominates the technologies of neural networks and machine learning, as this column suggested a couple weeks back, with its "TensorFlow" software, where Google contributes unending fundamental research into AI. These innovations filter down through its hardware devices, such as the Pixel phone, and into important applications in healthcare such as detecting breast cancer and other diseases. The list of technology breakthroughs is truly bracing.

It's a wonder, then, that Google isn't more than a one-product company. Alphabet's (GOOGL) - Get Report biggest unit, Google's revenue of $33.7 billion last quarter was comprised overwhelmingly -- 86%, in fact -- of advertising revenue, including its YouTube operation. The balance, dubbed "other revenue," is made up of a few products, including its commissions from the Google Play application store, its cloud computing business and its hardware sales of smartphones and Google Home. 

Among those latter offerings, revenue from taking a cut of people's apps is really the bulk, meaning that Google's second-largest business, being a retailer of code, is not that far from its main business of being a keyword search operator. 

Google's most ambitious-sounding projects, the "Other Bets" category, which includes its Verily Health Sciences health subsidiary (which made, and then put on hold, glucose-sensing contact lenses) and its Waymo self-driving car unit, brought in just $146 million last quarter, barely enough to make any one of those projects individually a noteworthy commercial business.  

And so, in twenty years in existence, the company that promised to organize the world's information hasn't really moved far from the original project of directing buyers to a showcase to generate sales, whether by keyword search or by shelf space, in the case of applications.

That fact hasn't hurt the stock very much, with shares returning over 31% in the last two years, double the S&P 500's return. But given that Amazon.com (AMZN) - Get Report shares nearly doubled in that time, one can ask if Wall Street isn't a bit disappointed with what it expects will have been about 24% revenue growth in the year just ended, and 18% this year.  

At a projected $163 billion in 2019 revenue, double-digit growth is quite impressive. But there's always that nagging question with Google: Why doesn't more of its innovation turn into a greater diversity in revenue? 

The easy answer is that Google was handed one of the biggest possible markets at its inception, and it was such a big market, Google has never found anything that can compare in scope. Digital advertising had already been proven by numerous competitors when Google entered the fray, including Yahoo! and a bunch of others that were like the Seven Dwarves -- Infoseek, AltaVista, Excite, Lycos, etc.

Google has failed, however, to find its next giant market despite a slew of big-ticket acquisitions. Those include buying the mobile computing division of Taiwan's HTC last year for a little over $1 billion, $3 billion spent on home gadget maker Nest in 2014, $1.3 billion for crowd-sourcing firm Waze in 2013 and over $9 billion spent in 2012 to buy Motorola Mobility.

Google's CEO, Sundar Pichai, was asked about Google's nascent businesses, the things in that "Other" category, in October, during the company's most recent earnings call. Analyst Justin Post of Merrill Lynch observed that there are "a lot of interesting things going on with YouTube and Waymo and Cloud and other areas," and asked, "As you look out two or three years, do you think any of these businesses could really make a financial positive difference on the bottom line for overall Google?"

Pichai answered, "we are focused on real large opportunities [...] but we take a very long-term view. And we want to invest to get the user experience right. And we are pretty confident that when we do that, the value will follow."

Perhaps, but it tests Wall Street's patience to some degree, in the meantime. Either there are no more worlds to conquer, which seems unlikely, or the company is failing to identify them. The third and more likely possibility is that for all the innovation, Google is asking the wrong question about what the fundamental business problem is that needs to be solved in order for it to monetize those markets. 

Alphabet's Q4 earnings report after the market close on Feb. 4 will offer the Street another chance to ask the question "Whither Google?" The answer will likely be just as opaque as it has been for some time now, even if the numbers look great once again.

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The author does not own, nor trade in, shares of any companies mentioned in this article.