Based on NIST's cloud definition, I describe IaaS, PaaS and SaaS, as well as public, private and hybrid clouds. I wrap up commenting on some recent ITaaS examples. Table of contents bellow. More about the author at . TABLE OF CONTENTS 00:00 Introduction 02:08 IT Stack 03:59 Service Delivery Models 08:52 Cloud Brokers 10:16 Service Model Economics 11:57 IaaS is a commodity 15:24 Deployment Models 19:34 IT-as-a-Service