Even cloud detractors have to admit that the Amazon cloud, which the company launched in 2006, has changed the foundation of IT. In some circles, the company is known more for its utility computing infrastructure, Amazon Web Services, than for its online mega-store.

Just how big is that infrastructure, we all want to know. Last month, we learned there may be a half-million servers behind that cloud. But how does that compare to, say, the entire Internet?

According to analysis performed by market research firm DeepField Networks, the Amazon infrastructure has staked out a significant portion of the Internet landscape.

In the wake of recent Amazon news, like the expansion of the S3 storage service, DeepField wanted to uncover the full reach of the Internet company. They started by asking “how frequently will a typically Internet user visit a web site based on Amazon infrastructure?”

The answer is rather astounding: on any given day, one-third of Internet users will touch an Amazon website.

To arrive at this calculation, DeepField analyzed AWS network data from a sample of a several million Internet end-users located primarily in North America.

Craig Labovitz, co-founder and CEO of DeepField, revealed the information in a blog post, noting that the one-third figure “is all the more impressive when you consider that our data includes millions of users and end devices of limited scope or activities, such as users who only check mail and home game consoles.”

DeepField also determined that as of April 2012, one percent of all consumer Internet traffic in North America is due to the Amazon cloud.

“This is a huge number given that Amazon, unlike, say Google, does not typically host massive video content,” writes Labovitz.

Their final query examined what companies were the biggest users of Amazon’s datacenters. To do this, they calculated the average percentage of all subscribers that access one or more Amazon sites each day. In first place is truste.com, purveyor of online privacy solutions, followed by InviteMedia, Chartbeat, Evidon and Ad Safe Media. Netflix is in the 8^th spot, while Dropbox comes in at 13. Instagram, another company in the news lately, is the 14^th biggest user.

“The number of websites that would now break if Amazon were to go down, and the growing pervasiveness of Amazon behind the scenes, is really quite impressive,” Labovitz tells Wired.

“Overall, Amazon enjoys a commanding lead in the much balleyhooed, mind-blowingly large $200 billion anticipated cloud computing market,” notes Labovitz. “But the war for cloud dominance is just beginning. Companies like Rackspace, CSC, Microsoft and Google are investing billions in datacenters and software to compete.”

For the privacy conscious, Labovitz reminds us that “although most consumers remain blissfully unaware, almost every web page they visit is tracked, analyzed and scored by dozens of analytics and marketing companies (a large number of them using Amazon infrastructure).”