A cloud Internet hosting service means that every single part of your world-wide web presence will be taken care of by an independent server. For example, your files and databases will be maintained by different machines and since just a single type of processes will run on a server, each machine will perform better and will use its resources to the highest. Whether you will get a real cloud service or not also depends on the control panel that you'll use to manage your account. Because most control panels were intended to work on a single server, they are unable to work on a cloud platform whatever a given web hosting service provider may advertise. In the event that one service stops responding, the whole server could go offline, so your sites will not be accessible. That's why you should check what service you will actually get if you are looking for cloud hosting before you buy anything.