In the hosting world, overselling means advertising features which a client will pay for, but cannot really get. Several of the options of a given website hosting plan can belong to this category - disk space, traffic, database storage space, etc. A plan may come with limitless disk space, for example, yet many hosting suppliers set up accounts on just a single server that can have a limited number of disk drives and considering 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 in order to guarantee that every single customer has their own share, even though everybody has paid for limitless space. Since most internet hosting Control Panels are meant to work on one server, many service providers don't have any choice but to oversell, that's nothing else but tricking their customers.