Amazon (AMZN 1.49%) stock is a very particular case. Investors typically either love or hate the company, and it's hard to find a middle ground. Amazon is up by a whopping 30% in the last quarter alone, trading near historical highs as bulls reacted with effervescent optimism to the company's earnings report for the last quarter of 2014. On the other hand, with the company scheduled to report earnings on April 23, the bears will be coming to the rematch in a vindictive mood.

The context
Amazon stock was down by more than 20% during the year leading to its latest earnings report, so the bears were ahead of the bulls by a considerable margin. But things took a dramatic turn after Amazon reported better than expected earnings for the fourth quarter.

Total sales during the last quarter grew 15%, to $29.33 billion. Excluding the negative impact from foreign currency fluctuations, net sales increased 18% year over year. The number was marginally below Wall Street forecasts; however, considering that currency headwinds were a big drag during the quarter, sales growth was still quite encouraging for a company as big as Amazon.

Besides, Amazon crushed earnings estimates, as earnings per share were $0.45 during the quarter, comfortably above estimates for net gain of $0.17 per share.

Investors had more reasons for optimism beyond financial figures; management disclosed that Amazon Prime membership increased by 53% during 2014 "on a base of tens of millions." Since Amazon Prime is an enormously valuable tool to consolidate customer loyalty, this speaks wonders about the health of Amazon's market leadership in online retail.

In addition, Amazon said it now has over one million worldwide active Amazon Web Services customers in its cloud computing segment. Amazon will start reporting financial performance for its AWS cloud computing business starting this quarter, which suggests the business is getting big enough to merit increased financial disclosure.

On sales and earnings
Management is expecting sales for the first quarter of 2015 to be in the range of $20.9 billion to $22.9 billion, an annual increase of 6% to 16%. Operating results are forecasted to be between a $450 million operating loss and a $50 million operating gain, compared to an operating gain of $146 million in the first quarter last year.

Amazon tends to provide enormously wide earnings guidance, which could be interpreted as the company's way of telling investors and analysts that short-term financial figures are not a priority for management.

For what it's worth, Wall Street is, on average, forecasting $22.43 billion in total sales during the coming quarter, a year-over-year increase of 14%. Analysts are on average expecting a net loss of $0.12 per share, considerably worse than the net gain of $0.23 per share Amazon reported in the first quarter of 2014.

Taking a deep look at Amazon Web Services
Since Amazon will be reporting financial performance for its AWS segment for the first time ever in the coming release, the segment will probably gather a lot of attention, and investors may want to take a deep look at numbers from this division.

According to data from the RightScale 2015 State of the Cloud Report, Amazon owns a gargantuan market share of 57% in public cloud usage with AWS, so the company is the undisputed leader in a promising growth industry. This means AWS could be a powerful growth driver for Amazon in the years ahead.

Importantly, having more information regarding AWS and its impact on overall company-level profitability could provide some much-awaited visibility regarding Amazon's profit margins. The AWS division is broadly believed to be a major drag on overall margins, as the company is investing tons of money in this segment.

If the numbers show that Amazon is doing better than expected in online retail, this could be a major victory for the bulls, as it would show that most of the margin pressure comes from AWS, a relatively young segment offering a lot of room for growing sales and expanding profitability over the long term.

Overall sales and earnings are important, but investors need to pay close attention to the impact of different business segments on the company's financial statements, since this could be remarkably enlightening in terms of understanding the true health and potential of Amazon.