"Today the hard drive goes away, and we replace the hard drive," announced Dropbox CEO Drew Houston last week at the company's first ever developer conference.

He went on to outline a future in which all the data apps need is stored online, turning phones and computers into mere metal portals to the web.

Could this be the future for app developers? Maybe, but according to some experts, cloud storage literally replacing the hard drive is definitely not happening "today."

"It's a great marketing message," says Terri McClure, a senior analyst at the Enterprise Strategy Group (ESG) who helps track about 60 cloud storage companies, "but from a practicality standpoint, I don't think it makes a lot of sense right now."

Dropbox's own product contradicts its new mission by mirroring the files stored on a hard drive, and its most recent target market, business users, has been somewhat reluctant to jump into the cloud. According to a survey of about 500 IT professionals by ESG, just 28% had implemented cloud storage solutions, though 33% had plans to open corporate cloud storage accounts within two years.

Even some Dropbox competitors think an all-cloud world is unfeasible. "It's just like the paperless office is never going to be happening," says Vineet Jain, the CEO of a company called Egnyte that provides cloud storage for enterprise customers.

Clearly, the drive-less future is a hard sell. Here are three reasons why:

  • Compliance And Security: Regulations that protect consumer data may contribute to health and financial companies' qualms about storing data in a third-party cloud like Dropbox. Even if a vendor says it complies with these standards, as Box did this April, responsibility for compliance lies on each individual company. Many of them aren't ready to put that much trust in the cloud–especially when Dropbox has investigated security breaches in the past. Furthermore, regulations weren't written with the option of cloud storage in mind. A privacy law in Canada, for instance, prohibits health data from being stored outside the country. If it's in the cloud, where is it geographically?
  • Internet Accessibility: Until the Internet blankets the world, there will be times when you'll access documents offline. Dropbox's new Datastores API helps sync offline changes to files once you're connected again, but you can't retrieve files without logging on. "You don't want to stop at the next local Wi-Fi Starbucks every time you want to access something," McClure says.
  • Latency: One of Jain's customers is a construction company with more than 200 terabytes of data. In order to download just two terabytes of that data from the cloud, he estimates it would take a week. That's not so convenient, especially when you're being audited or subpoenaed.

Hard drive obsolescence isn't impossible, McClure says. The Internet will get faster and more ubiquitous. Privacy regulations may address cloud storage, providing some peace of mind to businesses who use it. More likely than a drive-less future, however, is a future in which cloud and local storage complement each other, with the cloud providing storage expansion and a vehicle for multiple collaborators to share a file.

"To say all data will live in the cloud, I don't buy that," Jain says. "And I'm not going to buy that for at least a decade."

[Image: Flickr user Jared and Corin]