A web hosting service is a type of Internet hosting service that allows individuals and organizations to provide their own websites accessible via the World Wide Web. Web hosts are companies that provide space on a server they own for use by their clients as well as providing Internet connectivity, typically in a data center. Webhosts can also provide data center space and connectivity to the Internet for servers they do not own to be located in their data center, called colocation.

Service scope
The scopes of hosting services vary widely. The most basic is webpage and small-scale file hosting, where files can be uploaded via File Transfer Protocol (FTP) or a Web interface. The files are usually delivered to the Web "as is" or with little processing. Many Internet service providers (ISPs) offer this service for free to their subscribers. People can also obtain Web page hosting from other, alternative service providers. Web page hosting is typically free, advertisement-sponsored, or cheap.
Web page hosting is generally sufficient only for personal web pages. A complex site calls for a more comprehensive package that provides database support and application development platforms (e.g. PHP, Java, and ASP.NET). These facilities allow the customers to write or install scripts for applications like forums and content management. For e-commerce, SSL is also required.
The host may also provide a Web interface control panel (e.g. cPanel, Hosting Controller, Plesk or View a list of Control panels) for managing the Web server and installing scripts as well as other services like e-mail. Control panels and web interfaces have been causing some controversy lately as Web.com claims that it holds patent rights to the hosting technology with its 19 patents. Hostopia, a large wholesale host, recently purchased a license to use that technology from web.com for 10% of retail revenues[1]. Web.com recently sued Godaddy as well for similar patent infringement
Some hosts specialize in certain software or services (e.g. e-commerce). They are commonly used by larger companies to outsource network infrastructure to a hosting company. To find a web hosting company, there are searchable directories that can be used.
Hosting Reliability and Uptime
Multiple racks of servers, and how a datacenter commonly looks.
Hosting uptime refers to the percentage of time the host is accessible via the internet. Many hosting providers state that they aim for a 99.9% uptime, but there may be server restarts and planned (or unplanned) maintenance in any web hosting environment.
A popular claim from the popular hosting providers is '99% or 99.9% server uptime' but this often refers only to a server being powered on and doesn't account for network downtime. Real downtime can potentially be larger than the percentage guaranteed by the hosting provider. Many providers tie uptime, and accessibility, into their own Service Level Agreement, or SLA. SLAs may or may not include refunds, or reduced costs if performance goals are not met.
If you were to think of the uptime percentages offered by providers, over a given year you would have the following downtime:
100% - 0 hours 0 minutes
99.9% - 8 hours 46 minutes
99.5% - 43 hours 50 minutes
99.0% - 87 hours 39 minutes
98.0% - 175 hours 19 minutes
Types of hosting
A typical server "cage," commonly seen in colocation centres.
Internet hosting services can run Web servers; see Internet hosting services.
Hosting services limited to the Web:
Free web hosting service: is free, (sometimes) advertisement-supported web hosting, and is extremely limited when compared to paid hosting.
Shared web hosting service: one's Web site is placed on the same server as many other sites, ranging from a few to hundreds or thousands. Typically, all domains may share a common pool of server resources, such as RAM and the CPU.
Reseller web hosting: allows clients to become web hosts themselves. Resellers could function, for individual domains, under any combination of these listed types of hosting, depending on who they are affiliated with as a provider.
Virtual Dedicated Server: slicing up a server into virtual servers. each user feels like they're on their own dedicated server, but they're actually sharing a server with many other users.
Dedicated hosting service: the user gets his or her own Web server and gains full control over it (root access for Linux/administrator access for Windows); however, the user typically does not own the server.
Colocation web hosting service: similar to the dedicated web hosting service, but the user owns the server; the hosting company provides physical space that the server takes up and takes care of the server. This is the most powerful and expensive type of the web hosting service. In most cases, the colocation provider may provide little to no support directly for their client's machine, providing only the electrical, Internet access, and storage facilities for the server.
Clustered hosting: having multiple servers hosting the same content for better resource utilization. Wikipedia's own servers are a good example of this.
Some specific Web services:
File hosting service: hosts not web pages but files
Image hosting service
Video hosting service
Blog hosting service
One-click hosting
Shopping cart software

Obtaining hosting
Web hosting is often provided as part of a general Internet access plan; there are many free and paid providers offering these services.
A customer needs to evaluate the requirements of the application to choose what kind of hosting to use. Such considerations include database server software, scripting software, and operating system. Most hosting providers provide Linux-based web hosting which offers a wide range of different software. A typical configuration for a Linux server is the LAMP platform: Linux, Apache, MySQL, and PHP/Perl/Python.
Web hosting packages often include a Web Content Management System, so the end-user doesn't have to worry about the more technical aspects .