Amazon reported impressive Q3 2021 earnings and revenue with strong growth in its cloud and advertisement businesses leading the way.Revenue increased by 11% YoY to $158.88bn, beating the consensus estimate of $157.2bn.Amazon delivered an operating profit of $17.4 billion, up from $11.2 billion in the same period last year.Operating profit of Amazon Web Services Inc. (AWS) was $10.45bn, accounting for 60% of the company's total profit.AWS experienced sales acceleration of 19% in Q3 2021, compared to 12% YoY growth in the same quarter last year.Amazon is buying up chips and focusing on cost-cutting, enhancing efficiency to improve the bottom lineAmazon's advertisement business is growing, and its sales rose 19% YoY to $14.3bn, showing the most encouraging growth out of all the industry rivals.Amazon CFO Brian Olsavsky said the bulk of the company's capex spending is going toward technology infrastructure.Amazon expects to spend $75bn in fiscal 2024, and even more in fiscal 2025, driven mainly by generative AI.Investors placed high bets on AWS, Alexa, and the advertisement business and increased Amazon's stock prices by 5% in after-hours trading.