Cloud computing involves delivering data storage, servers, databases, networking, software and other services over the Internet. There are four types of cloud computing structures - private, public, hybrid and multiclouds - as well as three main service types: infrastructure-as-a-service, platform-as-a-service and software-as-a-service. Examples of cloud computing include file storage services like Dropbox and infrastructure services from Microsoft Azure and Rackspace. The main concept is enabling ubiquitous access to configurable computing resources over a network that can be quickly provisioned with minimal management.