Cloud Offerings
Infrastructure as a Service (IAAS)
Running a VM in someone else's datacenter. Leverage their power, networking, storage, etc. Easy to scale and provision what you need.
Platform as a Service
Abstracts away the OS so you can run your applications without worrying about the underlying infrastructure.
Software as a Service
Software like Exchange, SharePoint Online, Office 365, Salesforce, well as APIs that you use in your own applications. E.g. address verification, credit card verification, etc.