I. SaaS provides software to users over the internet, allowing access from any device with a connection. Examples include Google Docs, GitHub, and youRoom.
II. Amazon EC2/S3 provides cloud computing infrastructure as a service, allowing users to rent computing power and storage. This model provides sustainability by reducing upfront costs and shifting to pay-per-use.
III. SaaS prioritizes maintainability through centralized updates and hosting on provider infrastructure. Users benefit from automatic updates and support is provided by the SaaS vendor rather than relying on in-house IT teams.