A cloud Internet hosting service means that each part of your online presence will be taken care of by a different server. For instance, your files and databases will be maintained 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 resources to the highest. Whether you'll get a true cloud service or not also depends on the control panel that you'll use to handle your account. As most control panels were intended to work on a single server, they can't work on a cloud platform whatever a given hosting provider would advertise. In case one service stops responding, the whole server may go down, so your websites won't be accessible. This is the reason why you should check what service you'll actually receive if you are looking for cloud hosting before you buy anything.