But whether his company built its application on Microsoft or Oracle or SAP, there would still be a certain amount of lock-in to that platform in terms of maintaining it over the years and depending on that vendor for upgrades, Roche said.

"You can't create a way of not getting locked into Oracle or SAP," agreed Narinder Singh, founder of Appirio, a Force.com customer based in San Francisco. Appirio provides consulting for companies about how to use on-demand services and offers applications that connect the dots between Google Apps and Salesforce.com.

Singh, who previously worked at SAP, said the biggest barrier to winning over chief information officers with the platform-as-a-service notion is to break through preconceived notions of how software should be built.

"I can't overemphasize that enough. You have to get to where someone will say, 'I've never seen enterprise software before' to win them over," Singh said.

Singh acknowledged that in the early adopter phase of platforms such as Force.com, new applications will inevitably be tied to Salesforce.com's salesforce automation service. But eventually, companies will start to see the value of building applications in the cloud that can stand on their own, and other traditional application-development companies like Microsoft will have to respond with their own platform-as-a-service offerings.

Another criticism of Force.com is that building applications in its Apex development language and on an intrinsically proprietary platform doesn't give developers as much flexibility in creating applications as they would have using on-premise Java or .Net infrastructure.

Jonathan Snyder, CTO of Dreambulider Investments, agreed that "there are limitations" to writing applications on Force.com. But for the 10-person mortgage investment company in New York, the time and cost savings far outweigh those limitations.

"For us, we're a small company, we don't have the resources to focus on buying servers and developing from scratch," he said. "For us, Force.com was really a jump-start."

Companies such as Snyder's, as well as those in the midmarket, are certainly in the sweet spot for Force.com, said RedMonk's Cote.

"It seems to me that the real advantage of the platform as a service is ... in the midmarket," he said. "It's something they can afford to use. That's one of the more positive, exciting aspects of it. Hopefully, it opens up these features to a wider market of people."

In his presentation this week, Salesforce.com's Benioff recognized the possibilities of a platform such as Force.com not only for smaller businesses in the U.S., but also for companies in developing countries where building software-development infrastructure is cost-prohibitive.

Software development "has been expensive, complex and risky" and "does not serve emerging countries," he said. "Cloud computing offers a different choice."

Now for Salesforce.com, Google and others in the emerging market for cloud computing infrastructure, it remains to be seen how many businesses are willing to make that choice.