What happens when representatives from Web 2.0 poster children Google, Amazon, and Salesforce.com try to convince a group of seasoned IT pros that they should put all their data in the so-called cloud and leave it to outsiders to manage?

The result is interest and intrigue, and a healthy dose of caution.

"I get concerned about choices that in the long term might lock me in" to a single vendor, said Richard Mickool, chief technology officer at Northeastern University's Information Services unit, offering one reason why he's unlikely to hand off the bulk of the school's computing needs to an Internet vendor any time soon.

Mickool was one of a handful of execs representing IT buyers on a panel Monday at the Enterprise 2.0 conference's "An Evening In The Cloud" session in Boston. He was joined by California Public Utilities Commission CIO Carolyn Lawson and Sudler & Hennessey CIO Mary Sobiechowski, along with Richard Soley, CEO of standards body Object Management Group.

The user group fielded live vendor pitches from Amazon, Salesforce, and Google, whose reps were seated on the opposite side of a stage at the Westin Waterfront hotel before an audience of about 200 business technology managers.

The room was filled to capacity, an indication that businesses are serious, if somewhat reserved, about cloud computing -- an IT model in which data and applications reside on Web servers hosted and managed by third parties.

The vendors attempted to convince the users that the cloud is cheaper, faster, more secure, and more flexible than traditional client-server setups. "Eighty percent of IT dollars don't contribute to business change or growth," said Jeff Keltner, business applications development manager at Google. "Cloud computing is a large part of the answer."

Keltner and the other vendor reps argued that their companies' scale means they can spend billions of more dollars developing efficient IT infrastructures than most individual businesses can -- and that customers should take advantage. "Amazon's here to make electricity so you don't have to," said Adam Selipsky, VP for developer relations at the online retailer's Web Services unit.

Selipsky was referring to an analogy frequently invoked by cloud computing vendors -- that it makes about as much sense for businesses to run their own IT infrastructures and software as it does for them to operate their own power plants.

Cloud computing, said Salesforce.com senior VP Ross Piper, offers IT that is "safer, easier, and lower risk." He noted that financial services giant Morgan Stanley taps recruiting software through Salesforce's online platform.

Not so fast, the users countered.

Lawson, of California Public Utilities, said she's "a big fan" of the cloud computing concept, but noted that numerous government regulations across various industries could prevent businesses from handing off sensitive data to an Internet company. And privacy issues could emerge if government bodies dump their information into the cloud.

"We have your social security numbers ... we know where your children go to school," Lawson said.

Sobiechowski, of healthcare advertising and marketing agency Sudler & Hennessey, questioned whether the cloud has the capacity for quickly shunting around the sort of large, digital files typically found in an agency environment. "There's bandwidth issues," she said. "We also need real fast processing."

Object Management Group's Soley wondered if the standards are in place to ensure portability across the cloud. "How easily could I pick up my application from one vendor and move it to another?" said Soley.

The vendors agreed that cloud computing isn't the answer for all businesses, or all applications -- at least not yet. But they argued that the technology has reached the point where companies should consider offloading some of their computing needs to the Web. "It doesn't have to be all or nothing," said Piper.