The document discusses the evolution of software delivery models from on-premise to ASP to SaaS. It notes that while ASPs aimed to address limitations of on-premise, they still relied on outdated client-server technologies. True SaaS delivers advantages like instant implementations and upgrades, lower TCO through predictable subscription pricing, and the ability for customers to customize without vendor involvement. ServiceNow is highlighted as an example of a SaaS provider that allows full customization, automated upgrades, and a low-cost and flexible financial model.