Cloud computing is the on-demand delivery of IT resources and applications via the Internet with pay-as-you-go pricing. The presentation discusses the history of cloud computing starting in 1999 with Salesforce.com pioneering software-as-a-service, followed by expansions from Microsoft, IBM, Amazon, Google and others. It also covers the key characteristics like scalability, elasticity, and pay-per-use model, as well as the layers of cloud computing infrastructure, platform and software as a service and the advantages of lower costs and flexibility along with disadvantages of security and privacy concerns.