A Virtual Private Server is a type of website hosting that offers the users the benefits and liberty of owning a server, but without the costs of a private server feature. If you have a website that is fully developing or you only need more resources than you currently benefit of, you should try to find a company that is able to offer you this solution.
Practically, the VPS server allows several users to benefit of the resources of a single server, but without the performance compromises that are needed in case of other hosting features, especially the shared method. A server can host several VPS accounts, each one acting totally independent. Every VPS account has a guaranteed bandwidth, its own RAM resources, processor and HDD space.
The advantage of VPS are numerous compared with a shared hosting solution, and it usually refers to security and confidentiality, guaranteed resources, reliability, and the freedom to run your own scripts, widgets and programs. Moreover, the costs of a single server are split between more users, so it is surely a better solution for the medium sized sites that are growing constantly. It is an intermediary solution to a private server, but a growing site will eventually need such a solution.