Dropbox stunned the tech world last month when it revealed it had spent the last two-and-a-half years moving about 90 percent of its operation off of the Amazon cloud. Meanwhile, its biggest rival, Box, is moving the other way.

Through a tool it calls Box Zones, Box is giving businesses in places like Germany, Ireland, Japan, and Singapore the option of storing their files on cloud services within their home region. "It basically enables customers to store their file data in the region of their choice," says Box founder and CEO Aaron Levie.

This is a way for businesses to comply with local privacy and security regulations. But it also shows another benefit of the cloud. The cloud allows a company like Box to simply and easily store data in regions where it doesn't really have a physical presence. Cloud computing services from companies like Amazon, Google, Microsoft, and IBM provide a simpler and easier way of building and running software. Rather than buying and installing your own hardware, you can rent computing power of over the Internet.

Nonetheless, Dropbox has moved its popular file-sharing service off of the cloud and onto its hardware. Some saw this as some sort of sign that the cloud is less than desirable. But in fact, Dropbox is the exception that proves the rule.

It's one of the rare examples of a company whose online operation has grown so large, it can save significant amounts of money by building—and seriously refining—its own infrastructure. Naturally, Amazon and Google and Microsoft and IBM charge a premium for their services, but you have to get pretty big to make up the difference with your own network of data centers, especially as cloud computing prices continue to drop amid increased competition.

Levie says that Dropbox's move, contrasted with the approach of his own company, shows how the cloud computing landscape has changed over the last two years. When Dropbox decided to move off of Amazon, he says, the cloud market was very much centered around Amazon. "You didn't have Google as a reliable competitor. You didn't have Microsoft Azure at any reliable scale. You really didn't have IBM at that point," he explains. "The cloud was really a single vendor market. I think that forced Dropbox to think about needing some redundancy and leverage." But now, there are many options for companies like Box. Indeed, Box is using two cloud partners: Amazon and IBM.

As the same time, it should be said, Dropbox is still using Amazon in Europe, an area where it continues to grow at a fast but unpredictable rate. Even when you leave the cloud, you can't entirely escape its pull.