The SPI Model
- SaaS – Software as a Service → provisioned UI &| [any kind of] API access (eg. hosted webapps [eg. webshops, salesforce, github, Akamai CDN, maybe even wikipedia counts as one])
- PaaS – Platform as a Service → provisioned software ecosystem (eg. Hadoop [eg. Amazon EMR], RDBMS [eg. Amazon RDS*], NoSQL clusters, WebLogics, Glassfishes, Tomcats)
- IaaS – Infrastructure as a Service → provisioned compute instances (eg. VM, storage [eg. Amazon EC2, S3], maybe even a leased HW in a colocation hosting site counts as one)
