While the market has been celebrating the fact that Amazon (NASDAQ:AMZN) actually made a profit in its fourth quarter, the company's quarterly report actually revealed some other important facts that could keep the profits coming in the long run.

CEO Jeff Bezos, who has often been criticized for spending too heavily at the expense of making money, detailed a number of ways those investments have paid off in the report. In addition, CFO Tom Szkutak conducted an earnings call after the results were released where he explained some of the company's future plans.

It was a day of triumph for Bezos since the company's profit of $214 million, or 45 cents a share, on revenue of $29.33 billion, exceeded estimates. In some ways, however, the report was a bit of a vindication for the CEO as it shows that his long-range planning and willingness to forgo short-term profits appears to be paying off.

Amazon Prime is growing

Bezos has spent heavily on Amazon Prime, adding video and music services as well as other premiums, including photo storage, to what was once a straight shipping offer.

"When we raised the price of Prime membership last year, we were confident that customers would continue to find it the best bargain in the history of shopping. The data is in and customers agree — on a base of tens of millions, worldwide paid membership grew 53% last year — 50% in the U.S. and even a bit faster outside the U.S.," said Bezos in the earnings report.

That growth is very important because Prime members spend almost twice as much as non-Prime members. Prime subscribers spend almost $538 a year versus the $320 per year spent by non-subscribers, according to a study conducted by RBC. The survey, conducted in June 2014, was based on the answers of just over 2,000 Amazon.com shoppers -- 708 Prime members and 1,357 non-Prime customers.

Amazon is hiring a lot of people

Amazon has been able turn a profit despite the fact that its workforce is growing. The company reported that it finished 2014 with 154,100 employees worldwide. The online retailer added 36,800 employees over the course of the year, with 4,600 of them coming on board during the holiday quarter. That's an increase from 117,300 at the end of 2013, a 31% increase.

The need for employees is one of the profit challenges for Amazon. Delivering goods requires people, warehouses, drivers, and others. To keep headcount down, the company continues to work on automating its process.

In 2014, according to the earnings report, Amazon unveiled its 8th generation fulfillment center which uses "robotics, vision systems, and almost 20 years of software and mechanical innovation to fulfill customer orders. During the holiday season, the fulfillment network included more than 15,000 robots in 10 fulfillment centers across the U.S."

Going forward, to remain profitable, the company will have to continue to automate and find ways to use more robots and less people.

Amazon has added a lot of workers at its fullfilment centers. Source: Amazon

Amazon Web Services is growing

While most investors think of Amazon as a retailer which makes some hardware (largely to facilitate book, video, and music sales), the company has a growing web services business. That piece of the pie, dubbed Amazon Web Services, has quietly grown to the point that the online giant will start breaking out its sales starting in the the first quarter, said Szkutak during the earnings call.

"We just think it's an appropriate way to look at our business for 2015," Szkutak said.

Amazon has never revealed any financial information for AWS, lumping it into the "other" category of North American sales. This segment, which includes, advertising services and co-branded credit cards produced $1.67 billion during the last quarter, up from $1.17 billion a year ago.

The company has given out little specific data on AWS -- probably because cloud service competitors Microsoft and Google do not break out specifics for their offerings in their earnings reports. But, the company admitted that AWS has more than one million active customers, something it first reported in November, according to GeekWire.

The company did report that AWS usage had grown 90% year-over-year for Q4 2014.

Built for the long-term

While the company's burgeoning payroll is a concern, it's one that Amazon can mitigate by continuing to expand its automation efforts.

The growth of Prime and AWS are building blocks that should lead to a strong future. Prime members are loyal customers who buy more from the retailer and AWS provides an ongoing stream of revenue not dependent upon retail customers.

Amazon may well have turned a corner. Bezos will, of course, continue to invest, but he has shown that ultimately those investments will pay off.