Lew Tucker (CTO, Sun Microsystems): Cloud computing is not so much a definition of a single term as a trend in service delivery. It's the movement of application services onto the Internet and the increased use of the Internet to access a variety of services traditionally originating from within a company's data center.
Werner Vogels (CTO, Amazon): If you run your services inside the company, privately, utilization becomes an issue. It amortizes your costs over a number of cycles. If you run services outside, on a public service, it is no longer an issue for you.
Greg Olsen (CTO, Coghead): Cloud computing presents a compelling opportunity for consumers of information technology and producers of information services.