Shared hosting, sometimes called shared services or virtual hosting is simply when multiple websites share the same server, thus reducing the cost for everyone.
With a shared hosting account, your site will usually be on a server with hundreds of other web sites. That may sound like a lot, but it usually works out extremely well because most sites don't generate enough traffic or use enough resources for it to become a problem.
Share hosting is suitable for personal sites, small businesses, and even medium sized businesses if their hosting needs fit within the parameters of a small business.
Most shared hosting providers offer substantially more disk space, data transfer, and email accounts than most people or businesses need. If every site used their quota, shared hosting would not work. But since few do, it actually works out quite nicely.
The only real problem with shared hosting is if the web host oversells. Overselling means the host has put too many sites on one server. A good server usually has at least a gigabyte of memory, but if thousands of sites have to fight it out for memory, CPU cycles, and bandwidth, it means all the sites will be slow. Fortunately, any good host will prevent this from becoming a problem in the first place.
The hosting service must include 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 power 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 works fine with a shared web hosting service. But on the other hand, shared hosting is cheaper than other types of hosting such as dedicated server hosting. Shared hosting usually has usage limits and hosting providers should have extensive reliability features in place.
Shared hosting typically uses a web-based control panel system, such as cPanel, DirectAdmin, Plesk, InterWorx, H-Sphere or one of many other control panel products. Most of the large hosting companies use their own custom developed control panel. Control panels and web interfaces can cause controversy, however, since web hosting companies sometimes sell the right to use their control panel system to others. Attempting to recreate the functionality of a specific control panel is common, which leads to many lawsuits over patent infringement.
Shared web hosting can also be done privately by sharing the cost of running a server in a colocation center; this is called cooperative hosting.
Shared hosting is of two types name-based and IP-based
In IP-based virtual hosting, also called dedicated IP hosting, each virtual host has a different IP address. The web server is configured with multiple physical network interfaces or virtual network interfaces on the same physical interface. The web server software uses the IP address the client connects to in order to determine which web site to show the user.
In name-based virtual hosting, also called shared IP hosting, the virtual hosts serve multiple hostnames on a single machine with a single IP address. This is possible because when a web browser requests a resource from a web server using HTTP/1.1 it includes the requested hostname as part of the request. The server uses this information to determine which web site to show the user.
Shared hosting plans are generally the easiest and most economical for personal and small business websites. A lot of e-commerce sites, blogs, professional portfolios, and other small sites are hosted on shared hosting.