What: Shares of Amazon.com (NASDAQ:AMZN) jumped 22.3% in the month of October, according to S&P Capital IQ data, driven by the e-commerce juggernaut's stellar third-quarter 2015 results. Amazon stock has more than doubled so far this year, handily outpacing the broader market's modest rise:

AMZN Chart

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So what: Amazon managed to grow revenue a staggering 23% year over year to $25.4 billion and operating income came in at $406 million during the quarter, up from an operating loss of $544 million at the same time last year. Meanwhile, net income swung to $79 million, or $0.17 per share, compared to a $0.95-per-share loss in the same year-ago period. Analysts, for their part, were modeling a net loss of $0.17 per share on revenue of just $24.9 billion. 

But what really drove Amazon's massive improvement was the rapid growth and profitability of Amazon Web Services, which encompasses things like Amazon's web hosting, storage, and cloud-based initiatives. AWS grew revenue more than 78% year over year to just under $2.085 billion and, after operating expenses of $1.56 billion, singlehandedly generated segment operating income of $521 million.   

Now what: For perspective on AWS' torrid pace of growth and recent contributions to overall results, keep in mind Amazon only just began specifically reporting AWS results outside of its "other" revenue bucket beginning with the first quarter of this year. Assuming AWS can continue growing at anywhere near this clip and maintain similar profit margins -- and keeping in mind Amazon's core retail operations are still as strong as ever -- I can't blame the market for so aggressively bidding up Amazon stock last month. Further going forward, I think investors have every right to be excited for what's to come.

Steve Symington has no position in any stocks mentioned. The Motley Fool owns shares of and recommends Amazon.com. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.