Hosting is a type of internet-service that allows individuals and organizations to host their websites on the Internet. Hosting companies are the organizations that provide the space on server that belongs to or is leased by the client. They are also providing Internet connectivity. Usually such servers are located in data-centers. Also hosting companies may provide the space in data-centers for the client servers - colocation.
The application of hosting services may be really vast. The most wide-spread form are web pages or hosting for files, when all content is transferred to server via FTP protocol or via the web interface. The files are usually delivered as is or with minimal modification.
The level of hosting is determined by the needs. For example, the hosting of the website that consists of one page, can be very cheap or even free of charge, because such website does not require big amount of resources.
Complex sites on the contrary require more resources and support for databases and development platforms, such as ColdFusion, Ruby, Java, PHP or ASP.NET. Such hosting allows the client to write or install ready scripts for such applications as forums or CMS. Hosting companies may also provide interface or control panel that allows to manage the server, to install scripts and other modules.