There will be internal (private) and external (public) clouds that you will have to deal with, but they are so much more complicated than the traditional terms — LAN, WAN, intranet, and extranet — can describe. For one, the term cloud denotes a fuzziness about where the application bits and data are hosted. This is not only because of the business requirement for fault-tolerance and performance (which means the application servers and data are usually hosted at multiple locations), but also because virtualization is becoming almost an essential component of cloud computing.