A cloud Internet hosting service means that every single part of your world-wide web presence will be maintained by a different server. For example, your files and databases will be handled by different machines and since just one single type of processes will run on a server, every machine will perform better and will use its resources to the highest. Whether you will get a true cloud service or not also depends on the CP that you'll use to control 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. If one service stops responding, the whole server could go down, so your sites won't be accessible. That's why you should check what service you'll actually receive if you are looking for cloud hosting before you buy anything.