Amazon (NASDAQ:AMZN) had an incredible 2017. It consistently beat earnings estimates, bought Whole Foods Market, and its stock price increased about 56%. Along the way, CEO Jeff Bezos became the wealthiest person in the world, surpassing $100 billion in net worth.

But investors don't buy shares of a company based on what happened in the past; they buy based on expectations for the future. Here's what investors can expect from Amazon in 2018.

An Amazon warehouse worker.

Image source: Amazon.

More video spending

Amazon launched Prime Video globally at the end of 2016, opening up the video streaming service to an additional 190 or so countries. The global launch provides additional scale for Amazon to leverage its video content spending, which reached an estimated $4.5 billion last year.

Investors should expect Amazon to spend even more on video content in 2018. Video is a key part of Amazon Prime. CFO Brian Olsavsky told analysts the video business "continues to drive better conversion of free trials, higher membership renewal rates for existing subscribers, and higher overall engagement." Prime members who watch video also spend more on Amazon, according to Olsavsky.

Prime members streamed more video in 2017 than ever before. Investors should expect that trend to continue this year as Amazon continues to invest in content and it makes partnerships with hardware makers.

Growing the advertising business

Amazon's ad business is quickly becoming a force to be reckoned with. While Amazon started its ad business about 10 years ago and used it as a way to offset the cost of Kindle devices, it's quickly becoming a multibillion dollar business. The company generated $2.8 billion in ad revenue last year, according to an estimate from J.P. Morgan analyst Doug Anmuth. Citi analyst Mark May thinks Amazon's ad business could bring in over $10 billion this year.

The advertising business benefits from the growth of Prime and Amazon as a destination for product searches. But Amazon still has room to expand its ad products to other publishers' websites. It remains in the very early stages of displaying ads on third-party websites, so look for Amazon to expand its ad products and improve its self-serve ad-buying platform.

More moves in groceries

Amazon's purchase of Whole Foods last year shows how serious Amazon is about selling groceries. AmazonFresh -- the company's fresh grocery delivery service -- has been around for about a decade, but it hasn't expanded to very many cities. Nonetheless, Amazon's grocery sales have continued to climb as more shoppers embrace online grocery shopping.

Amazon has already made a big move in its efforts to win grocery sales by opening its Amazon Go store to the public. The convenience store relies on cameras, sensors, and artificial intelligence to do away with checkout clerks. The idea is to replace marginal costs like employees with fixed costs to improve the long-term profitability of the brick-and-mortar store. Amazon could extend some of Amazon Go's technology to Whole Foods.

Additionally, Whole Foods provides the scale needed to expand AmazonFresh to a lot more markets. That could enable Amazon to lower the subscription price for Fresh, lower the minimum order threshold, or both. Such a move could result in a lot more people buying groceries on

An Amazon Echo device on a bookshelf.

Image source: Amazon.

Alexa in everything

Amazon's voice assistant, Alexa, has been a surprise hit. The Echo Dot was Amazon's most popular item during the holiday season last year.

Investors should look for Alexa to start showing up in even more devices as it licenses the technology to manufacturers. At CES this year, Alexa showed up in cars, smart glasses, and even a smart toilet (because that's necessary). Expect for even more devices to integrate Alexa technology this year.

The smart speaker trend is just getting started, and 2018 promises to be even bigger than 2017. What's more, Amazon's early moves in the space provide it with a moat, as most Alexa-enabled device owners say they'll buy another Alexa-enabled device.

Alexa provides a platform for Amazon to increase sales for both its retail operations and its advertising business.

More private labels

Amazon's private-label business is accelerating as the retailer dives into more and more verticals. From snack food to furniture to baby wipes, Amazon's labels generated about $450 million in sales last year. The addition of Whole Foods' 365 Everyday Value brand has been a big hit with customers so far.

Private-label products generally come with higher profit margins, so it behooves Amazon to continue expanding into new areas. Its data on shoppers provides some of the best information to inform product and label decisions, ensuring Amazon hits the mark more often than not. Amazon is also at an advantage when it comes to promoting its own products, highlighting them in search results.

Amazon's private label business should continue to expand in 2018, but it's still an extremely small part of Amazon's total sales.

Already off to a great start

Amazon investors are probably happy with the stock performance through the first month of 2018. The share price is already up another 20% after a stellar 2017. As long as Amazon continues to execute across its wide array of businesses, there's no reason the stock can't continue to outperform the market in 2018.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.