The recent rash of outages at Amazon, Citrix, and Google were a warning sign to CIOs contemplating the move to cloud computing, but service availability is just one of the things to worry about. Privacy, data security, and vendor lock-in are on their watch list, too.As my colleague Nick Hoover reported in "Outages Force Cloud Users To Rethink Tactics," IT departments that subscribe to cloud services are scurrying to devise backup plans for the inevitable minutes and unbearable hours when those services go on the blink.

Not long ago, we heard about some of the other issues that senior-level IT people say stand in the way of widespread adoption of cloud services. The venue was the Enterprise 2.0 conference in Boston, where I interviewed three of the panelists following an hour-long discussion that included representatives from Amazon, Google, and Salesforce.com.

Carolyn Lawson, CIO of the California Public Utilities Commission, says that public agencies simply have too much sensitive personal data -- birth certificates, addresses, driver's license and Social Security numbers, health information -- collected from their constituents to store it in the cloud. "That's the kind of information that members of the public and myself personally don't want out in the cloud," Lawson says. (See the Lawson video interview here.)

Richard Mickool, CTO and executive director of information services with Northeastern University, says it may be easy to move data and applications into cloud services, but he needs to know more about how to back out those services if he changes his mind. "I have to be comfortable that they're not locking me in," he says. "I really don't know the exit cost yet, what the total switching cost will be." (See the Mickool video interview here.)

Mary Sobiechowski, CIO and global director of IT with Sudler & Hennessey, a health care communications firm, isn't convinced that cloud service providers are able to accommodate the specialized, CPU- and bandwidth-intensive applications used at her company. That ability to do that in the cloud may still be five to 10 years away, she says. (See the Sobiechowski video interview here.)

Software as a service, storage as a service, and other cloud computing services are still in the early stages, and the adoption curve undoubtedly is pointed up. But as these CIOs and CTOs will tell you, there are still some serious hurdles to be cleared. How high are the hurdles for your company? Weigh in and let us know.