"We intercept the file system calls and fool the operating system into believing that the files are actually local on the device," Gauda explained. "We stream them to and from the cloud in real time, but we cache a lot of that information locally on every device. You can have a terabyte of information and only 16 gigs will be cached locally, but those are the 16 that you use most often."

The novel storage method holds out the promise of smoothing over access disruptions, a common complaint about cloud storage. If a user is travelling with an iPad, for example, and loses Internet access, with Bitcasa she can at least access the files she uses most frequently and those she has set to save to her device.

Gene Ruth, a research director at Gartner, said the startup offers improvements to the cloud storage market from a consumer's perspective, but the question is whether it can deliver.

"There's a lot of things they have to get right because this file sync and share business is not that easy," Ruth said.

Bitcasa will likely fail early if it fails, since at US$10 a month for unlimited storage, customers will almost certainly come apace, Ruth said. And if it succeeds, it will likely force the rest of the consumer cloud storage market to abandon storage limits.