A shared web hosting service refers to a web hosting service where many websites reside on one web server connected to the Internet. Each site "sits" on its own partition, or section/place on one server to keep it separate from other sites. This is generally the most economical option for hosting, as many people share the overall cost of server maintenance.
The hosting service includes system administration since it is shared by many users, this is a benefit for users who do not want to deal with it, but a hindrance to users who want more control. In general shared hosting will be inappropriate for users who require extensive software development outside what the hosting provider supports. Almost all applications intended to be on a standard web server work fine with a shared web hosting service.
Shared hosting typically uses a web-based control panel system, such as cPanel, Ensim, DirectAdmin, Plesk or one of many other control panel products. Most of the large hosting companies use their own custom developed control panel.