4.1. Defining Infrastructure as a Service (IaaS)4.1.1. IaaS workloads4.1.2. Pods, aggregation, and silos4.2. Defining Platform as a Service (PaaS)4.3. Defining Software as a Service (SaaS)4.3.1. SaaS characteristics4.3.2. Open SaaS and SOA4.3.3. Salesforce.com and CRM SaaS4.4. Defining Identity as a Service (IDaaS)4.4.1. What is an identity?4.4.2. Networked identity service classes4.4.3. Identity system codes of conduct4.4.4. IDaaS interoperability4.4.4.1. User authentication4.4.4.2. Authorization markup languages4.5. Defining Compliance as a Service (CaaS)4.6. Summary