In the hosting world, overselling means advertising features that a client pays for, but cannot really get. Several of the options of a given web hosting solution can belong to this category - hard disk space, traffic, database storage space, and many others. A package could come with unrestricted disk space, for example, but nearly all hosting service providers set up accounts on a single server which can have a limited number of disk drives and due to the fact that all customers upload content, there won't be any space left on the server sooner or later or there will be some secret quotas so as to guarantee that every single customer has their share, although everybody has paid for unrestricted space. As most hosting Control Panels are intended to work on one server, a large number of service providers don't have any choice but to oversell, which is nothing else but deceiving their customers.