There are several types of cloud service, and which one you are using can affect how and how much you can interact with your data. Three common categories are Software-as-a-Service (SaaS), Platform-as-a-Service (PaaS) and Infrastructure-as-a-Service (IaaS).
With SaaS, you are simply accessing software over the Internet that is offered and maintained entirely by the cloud provider. The type of software can include e-mail, content management systems, productivity software and business applications. SaaS requires the least amount of setup on the end-user's part, but also provides the least amount of control and flexibility as far as system functionality, and what can be uploaded or downloaded from the cloud.
With PaaS, the cloud host provides a hardware and software platform on which you can develop, install and run applications, Web sites or other services. You don't have direct access to the backend servers, but you have more control over what you can do on them.
With IaaS, the cloud host provides computing resources including physical or virtual servers, storage space and networking capabilities over which you have a lot of control. You are basically renting access to a portion of a data center's network and servers, and you can install and upload anything you want to them. You don't have the responsibility of maintaining or upgrading equipment, but do have to configure the servers and set up any software you might need. An IaaS service can be a public, private or hybrid cloud. Public clouds are shared by a number of users who select and access service over the Internet; private clouds allow users to have dedicated servers on a private network; hybrid clouds involve a little of both.
The types are not always mutually exclusive, as an SaaS provider might house their software on PaaS or IaaS cloud services, and a PaaS host might use the services of an IaaS provider. This potential nesting means that problems of a provider you don't even know you're using can cause issues with getting to your data or services.
And which type of service your company is using may determine things like who you contact when you have a problem -- someone in your own IT department versus a third party. It also impacts things like security, which, as you will see next, can affect your ability to work with your data.