A cloud Internet hosting service means that each and every part of your online presence will be handled by an independent server. For example, your files and databases will be maintained by different machines and since only one kind of processes will run on a server, every 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 CP that you will use to manage your account. Because most control panels were made to work on a single server, they cannot work on a cloud platform regardless of what a given web hosting provider may advertise. In case one service stops responding, the entire server may go offline, so your sites won't be accessible. This is the reason why you should check what service you'll actually receive in case you are looking for cloud hosting before you order anything.