Cloud Computing services.

1. PaaS - (Platform as a Service)

This type of serivice oriented to provide it's servers where they can run their applications instead of storing them in your own facilities. Those applications delivered to user by a public internet what is saving time and labour. With this technology, enterprise operations, or a third-party provider, can manage OSes, virtualization, servers, storage, networking, and the PaaS software itself. Developers, however, manage the applications.

e.g.:

• Google App Engine 
• Apprenda

     2. SaaS - (Software as a Service)

With this type of service software, developed, created and managed by a SaaS provider runs on computer, instead of installing and managing by user.

e.g.:

Google Gmail;

Salesforce;

    3. IaaS - (Infrastructure as a Service)

This cloud provides infrastructure(self-service) for managing,monitring, acessing infrastructure data such as compute, storage, networking, and other elements (security, tools) are provided by the IaaS provider via public Internet, VPN, or dedicated network connection. Users own and manage operating systems, applications, and information running on the infrastructure and pay by usage.