A cloud Internet hosting service means that every single part of your web presence will be handled by a different server. For example, your files and databases will be managed by separate machines and since just one kind of processes will run on a server, each machine will perform better and will use its resources to the highest. Whether you'll get a true cloud service or not also depends on the control panel that you will use to control your account. As most control panels were made to operate on a single server, they cannot work on a cloud platform regardless of what a given Internet hosting provider could advertise. If one service stops responding, the entire server may go down, so your websites will not be accessible. That's why you should check what service you'll actually get if you are looking for cloud web hosting before you purchase anything.