In shared hosting, the provider is generally responsible for management of servers, installation of server software, security updates, Technical support and other aspects of the service. The majority of servers are based on the Linux operating system - LAMP (software bundle), which is driven by the low cost of open source software. But some providers do offer Microsoft Windows-based or FreeBSD-based solutions. For example, the Plesk and Ensim control panels are both available for two operating systems, Linux and Windows. Versions for either OS have very similar interfaces and functionality, with the exception of OS-specific differences (for example, ASP.NET or Microsoft SQL Server support under Windows, and typically greater security and stability under Linux).
There are thousands of shared hosting providers in the United States alone. They range from mom-and-pop shops and small design firms to multi-million-dollar providers with hundreds of thousands of customers. A large portion of the shared web hosting market is driven through Pay Per Click advertising (PPC) or Affiliate programs.
Shared web hosting can also be done privately by sharing the cost of running a server in a co-location centre; this is called cooperative hosting.
