There is a difference between the public and private networks and in VPN-using case, it is important to note that when we are talking about the latter then there is no difference between the public and private networks. The latter refers to the web sites on the Internet which can be accessed by anyone irrespective of the location of the user. A VPN or Virtual Private Network is just an application that makes one feel secure while using the Internet. It helps one to make use of the internet without worrying about security threats and keeps all your activities protected and confidential. You should definitely try to understand this concept before you decide on a VPN service for yourself.