While total spending on cloud data centers continues to surge, earnings season revealed some pretty big differences in the spending growth seen by Internet and cloud giants.

On one end of the spectrum, Amazon.com (AMZN) - Get Report reported its purchases of property and equipment acquired under capital leases, which is fueled in large part by Amazon Web Services (AWS), fell 14% annually to $2.34 billion. For the trailing 12 months, such spending has totaled $9.63 billion, which represents a moderate 20% increase from the prior 12 months.

It's worth noting here that quarterly capex figures can be very lumpy, due to the timing of payments made for investments -- while AWS-related capex may have fallen slightly in Q2, it will almost certainly continue growing long-term. It's also worth keeping in mind that Amazon spends a lot on direct purchases of property and equipment. That spending, which is driven more by Amazon's warehouse and logistics investments, rose 34% over the trailing 12 months to $13.04 billion.

Regardless, the pace of Amazon's data center capex growth looks very different than Facebook's (FB) - Get Report : The social media giant's capital spending rose 140% in Q2 to $3.46 billion. And on its earnings call, Facebook reiterated a forecast for its capex to more than double in 2018 to roughly $15 billion, after having grown it by 50% last year to $6.73 billion.

Facebook also forecast its capex will keep rising in future years, without sharing any specific guidance. And thanks in part to its infrastructure spending, the company forecast its operating margin, which was at 50% in 2017, will decline to a mid-30s percentage over the next several years.

Alphabet's (GOOGL) - Get Report capex growth has also been pretty high, even if it's not as high as the official numbers suggest after one backs out the impact of real estate purchases. Over the first 6 months of 2018, the Google parent's purchases of property and equipment rose 139% to $12.78 billion. In 2017, such spending grew 31% to $13.09 billion.

Microsoft (MSFT) - Get Report is somewhere in between. The software giant's capex rose 24% annually in the June quarter to $4.1 billion, and over the whole of fiscal 2018 (it ended in June), its purchases of property and equipment grew 43% to $11.63 billion. Microsoft forecasts its capex will rise in fiscal 2019 as well, but hasn't shared any figures. The analyst consensus is for spending on property and equipment to grow 20% to nearly $14 billion.

Even if one's only looking at data center spending, it's impossible to assign just one reason for the differences in capex growth between these companies. The discretionary investment decisions made by a firm -- for example, to invest more in AI training systems, or to bring cloud infrastructure services to a new geographic region -- play a role. As do the growth rates seen for various services.

Microsoft's capex growth undoubtedly has much to do with the fact that its Azure public cloud unit has posted annual revenue growth rates between 89% and 97% over the last five quarters -- that's stronger than the 40%-plus growth rates Amazon Web Services (AWS) has been reporting off a larger base. The healthy growth seen by Office 365, LinkedIn and other platforms relying on Microsoft's data centers is also clearly playing a role.

However, when looking at the recent capex growth of tech giants, as well as the infrastructure-related spending of some smaller Internet firms such as Snap (SNAP) - Get Report and Twitter (TWTR) - Get Report , there is arguably one broader theme at play: Companies that need to support a lot of consumer-generated video are seeing their data center spending rise faster than those that don't.

Facebook now has four different apps (core Facebook, Instagram, Messenger and WhatsApp) that possess over 1 billion monthly active users (MAUs). And between them, these apps support a slew of popular services for the sharing of consumer-created video, from news feed video uploads to Stories videos to video calls to livestreaming. The cost of processing and storing all those video uploads adds up, as does the cost of streaming all of that content to a billion-plus consumers.

Likewise, though many of Google's popular consumer services (Search, Maps, Gmail, etc.) don't feature a large video component, the costs of supporting YouTube are clearly enormous. YouTube reported seeing over 1 billion hours of daily viewing back in early 2017, and in May the video giant reported having over 1.8 billion monthly logged-in users. And back in 2015, YouTube reported seeing over 400 hours of video uploaded every minute (the current number is likely much higher).

Amazon of course runs a very popular video service of its own in Prime Video, and also offers a slew of other digital content services. However, Prime Video doesn't involve consumer uploads, and -- considering that even Netflix (NFLX) - Get Report was only reporting 1 billion hours of viewing per week last year -- its traffic appears to be a fraction of YouTube's.

Amazon's data center spending appears to be driven far more by the needs of AWS and (to a lesser extent) its online retail operations, than by its consumer content services. That has implications both for its capex growth and its margin profile.

Though AWS-related capex should rise long-term, Amazon's income statement makes it clear that the company is getting a very good payoff for what it invests in the business, via the many high-margin public cloud services AWS provides to businesses. Over the first six months of 2018, AWS's operating income rose 68% to $3.04 billion.

Facebook has -- and will continue to -- get a very good ad revenue payoff for the data center investments it makes to support video and other services for consumers in developed markets. However, as its long-term margin guidance signals, the story is more complicated in developing markets where its average revenue per user (ARPU) is much lower and consumption of its video services is growing rapidly. Facebook might still profit from these users over the long run, but at lower margin than what it sees in the U.S. or Western Europe.

The same might hold for YouTube, which is believed to have seen tremendous U.S. ad revenue growth and has been working hard to grow emerging markets usage. As for Snap, which continues to see major cash burn, the company has suggested it prefers not to heavily promote its services in emerging markets for now, given how difficult it is for the company to service those users profitably.

For investors in many of the chip and hardware firms servicing cloud giants, such as Intel (INTC) - Get Report, Micron (MU) - Get Report, Broadcom (AVGO) - Get Reportand Arista Networks (ANET) - Get Report, the capital-intensity of supporting tons of consumer-generated video is welcome news. But for investors the companies footing the bill, it's a risk to keep an eye on, even if it's not necessarily something to panic over.

Amazon.com, Facebook, Alphabet and Microsoft are holdings in Jim Cramer's Action Alerts PLUS member club.