A cloud web hosting service means that each and every part of your online presence will be taken care of by a separate server. For instance, your files and databases will be managed by different machines and since just a single kind of processes will run on a server, every machine will perform better and will use its system resources to the highest. Whether you will get a true cloud service or not also depends on the control panel that you will use to manage your account. Because most control panels are designed to function on a single server, they can't work on a cloud platform regardless of what a given Internet hosting provider would advertise. In case one service stops responding, the whole server may go down, so your sites won't be accessible. That's why you should check what service you will actually get in case you are looking for cloud internet hosting before you purchase anything.