But all the high-flying documents stashed in free services such as Dropbox and SugarSync are becoming a concern to many companies. Customer information and trade secrets are sitting in servers outside managers' control -- often without their knowledge. It's sort of like oil spilling into the Gulf of Mexico, says Michael Suby, vice president of research at New York City-based Frost & Sullivan. "If you don't plug the holes that tap the well, you're not being responsible."
The problem is destined to grow as cloud file storage and sharing go more mainstream, experts say. The major Internet giants are all pushing into the market. Last week, Google announced a service dubbed Drive. Microsoft already has SkyDrive, and Apple has iCloud.
Related: Why Google Drive Won't Be a Dropbox Killer
But alternatives with more security and business-like features are readily available. Dropbox and SugarSync are expanding their offerings to provide low-cost, if basic, business versions that provide some additional controls. And a growing list of companies offer more sophisticated and secure services for business users, among them Accellion, Box, CX.com, Egnyte's HybridCloud,Oxygen Cloud, Wuala and YouSendIt. While some offer free starter accounts, paid services range from $15 to $500 a month or more, depending on the number of users and amount of data storage needed.
Jim Andersen, president of Foundation Management Associates, a financial consultancy to charitable organizations, stopped using Dropbox a year ago after two troubling incidents. First, an employee at a Haitian hospital client accidentally deleted a year of financial records from its computers, and Andersen's, with a single keystroke. Then, he almost lost a large new client because a state government it was tied to had blacklisted Dropbox.