"E-mail and calendaring are going to be killer apps for Web 2.0 technology," Dietzen said.

E-mail can be made more compelling by merging it more onto the Web, he said. Users should not be required to leave the context of what they are doing to tend to e-mail, said Diezten.

He also advised using existing infrastructure for Web 2.0. "Your focus is what's the application look like and how can I deliver some compelling value," said Dietzen.

SAP's Nolan, however, rejected the notion that Web 2.0 means replacing something that already exists. SAP is relatively secure in the new paradigm because users have spent hundreds of billions of dollars on applications and these will not be replaced, Nolan said.

"Shouldn't we really be thinking about the new applications that haven't even been thought about yet rather than replacing the ones that have already been built?" Nolan asked.