Cloud Infrastructure, like all infrastructure, still requires special care to ensure it's security. Some of the benefits of Cloud Infrastructure are the pay-as-you-go model (usually per second or per minute billing), flexibility to create and delete servers on demand or automatically and the ease of provisioning complex services like database clusters without highly specialized experts.
Cloud computing is the on-demand availability of computer system resources, especially data storage (cloud storage) and computing power, without direct active management by the user. Large clouds often have functions distributed over multiple locations, each location being a data center. Cloud computing relies on sharing of resources to achieve coherence and typically using a "pay-as-you-go" model which can help in reducing capital expenses but may also lead to unexpected operating expenses for unaware users.