Virtual Private Server is basically called as VPS is just a combination of both shared and dedicated hosting. It is best suited to operate mass data at one place without affecting others. Basically to have a web site you need to have a place to upload it, which is called hosting and purchasing a server may not only be expensive but also difficult.
When you rent a VPS server you are not affected by other server problems and you can manage your server as you wish and your comfort. This is very useful at places where you have heavy website traffic or highly interactive dynamic website or for whom who are expecting a great business along fast and rapid growth for themselves. When it comes to features such as a custom firewall, dedicated mail server or more control over security VPS serves you better compared to others and are also affordable. More over VPS allows unlimited domain hosting (like shared), multiple dedicated IPs, private name servers etc along with the option of using semi-managed or fully-managed solutions – all within your own private space. You can also decide whether you want cPanel or Plesk for your admin interface or nothing.
VPS servers are usually needed to manage large datas, mass mails. If you want to manage multiple mails from the same IP within all the staffs in a company or with your customers VPS are the best servers.
VPS are the best affordable servers with complete privacy as you don't share your operating system with anyone else and you have your own instances of all server applications such as Apache, PHP, and MySQL. If you need to have any of these services customized, you can make changes to suit the server according to your own needs. Unlike the other servers here you have adequate amount of RAM when and there no one to share it when you need the most. Also the main advantage is when you are installing any new application which requires the system to restart it is easy to do it without disturbing or affecting any one although you share the server technically with others.