Cloud computing and advertising were the 'strong contributors' to Amazon.com's growth in the fourth quarter, while shoppers threw their money at the e-commerce giant, giving the company a strong fourth-quarter sales growth.

Amazon.com, which has been investing in everything - from warehouses, robots, data centers, gadgets, advertising, entertainment and groceries - maintains its dominance in online shopping and cloud computing.

Chief Financial Officer Brian Olsavsky said Amazon Web Services, the company's profitable cloud-computing unit, and its emerging advertising business were strong contributors to sales growth and earnings. Revenue from AWS increased 45 percent to $5.1 billion, the company said in a statement.

Revenue gained 38 percent to $60.5 billion in the fourth quarter, the biggest increase in a holiday period since a 42 percent jump in 2009. Net income was $1.9 billion -- a record for the company.

Amazon is the e-commerce leader in the U.S. with its $99-a-year Prime subscription, which includes delivery discounts, music and video streaming. The company said it will continue the global expansion of the Amazon Fresh grocery delivery service and Prime Now, a one-hour delivery service, to strengthen Prime membership overseas.