The New York Times (NYT 0.18%) skyrocketed after its fourth-quarter earnings release, rising as much as about 16% the following trading day. Investors were likely pleased with the company's better-than-expected revenue and earnings per share. More specifically, New York Times likely impressed investors with the strong catalyst behind its better-than-anticipated quarter: breakneck growth in digital subscriptions.

New York Times CEO Mark Thompson shares shareholders' optimism for the newspaper's fast-growing digital business and the long tail market opportunity that comes along with it. "Digital is growing very rapidly, and ultimately I think there will be many times the number of digital subscribers compared to print," said New York Times CEO Mark Thompson in an interview with CNBC after the earnings release.

It's good to see management betting so bullishly on digital subscriptions. After all, the business is growing incredibly rapidly, and there're no signs of a slowdown.

A newspaper next to a tablet and a cup of coffee

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New York Times' soaring digital subscription business

In The New York Times' fourth quarter, revenue climbed 10.1% to $484.1 million, up from $439.7 million, easily beating analyst expectations for revenue of about $467 million. As management noted in its fourth-quarter press release, growth during the period was "primarily due to significant growth in recent quarters in the number of subscriptions to the Company's digital-only products."

Fourth-quarter revenue to New York Times' digital-only subscription products soared 51.2% year over year. This was comprised of a 50.1% year-over-year jump in digital-only news product subscription revenue and a 76.6% rise in "other product" subscription revenue (revenue from its stand-alone digital crossword and cooking products). Of course, digital-only news subscriptions represented for the bulk of the New York Times' total growth in digital-only subscriptions, since it accounted for 95% of the segment's revenue. Excluding the benefit of The New York Times' extra week in its fourth quarter, revenue from digital-only subscription products increased 40.1% year over year.

Propelling this growth, New York Times added 99,000 net digital news subscriptions and 58,000 net digital subscriptions to its crossword and cooking products.

Full-year growth in digital-only subscription revenue was similarly promising, rising 46% year over year, with 45.9% growth in news product subscription revenue and 53.6% growth in other product subscription revenue.

Suffice it to say, digital subscriptions are a no-joke catalyst for The New York Times.

More reasons to be bullish on digital subscriptions

Interestingly, a bullish case can be made for digital subscriptions in general. To see how rapidly consumers are willingly signing up for digital subscriptions, look to some recent figures provided by Apple (AAPL 1.27%) and (AMZN -1.64%) on the growth of subscriptions on their platforms.

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Image source: Getty Images.

Apple has been regularly touting rapid growth of digital subscriptions across its services offerings for some time now. Revamping its App Store policies in 2016 to allow subscriptions across all app categories, Apple has seen strong growth in subscriptions ever since. In its fiscal fourth quarter of 2017, for instance, Apple said total subscriptions reached over 210 million, up 25 million in just 90 days. Apple's first-quarter paid subscribers were 240 million, up 58% year over year. Further, Apple said in its fourth-quarter earnings call it has also seen strong, 75% year-over-year growth in paid subscribers for its own Apple Music service.

Meanwhile, Amazon's subscription services revenue, which the company says includes revenue from its Amazon Prime membership, as well as audiobook, e-book, digital video, digital music, and other services, is similarly soaring. Subscription services revenue in Amazon's fourth quarter soared 49% year over year.

Sure, neither Apple or Amazon are newspaper companies. But it's clear that consumers are gobbling up subscriptions, from streaming-TV to gaming platforms. Companies have good reason to pursue digital subscriptions -- especially if they've already proven their subscription services are a hit with consumers the way The New York Times has.

Editor's note: A previous version of this article mistakenly cited Apple's fourth-quarter data on paid subscribers as data from its most recent quarter. Apple's fiscal year ends on Sept. 30. The article has been updated.