A proxy server is a computer at another I.P. address that you connect to and from there to a selected site. In this way, the Internet Postal Address will not be your's but that of the Proxy Server. When you arrive at your chosen destination it will appear that wherever the Proxy it; be it Chicago or Katmandu, that is where you are.
The use of Proxy Servers are most vital to escape Censorship. This is not only true in China, this is true in many other places which do not allow you to connect to specific other sites. For example, your school computer might have Facebook blocked. To get to Facebook you would connect to a Proxy and from the Proxy to Facebook. The computer you are using will record you went to the Proxy Site. Facebook will record that you arrived from the Proxy.
Years ago there were so many excellent Proxy Servers that one often had a slurry of them available to be used. Today?
I needed a proxy server. It took me the better part of two hours to find one.
Firstly, all the old ones had been closed down so one would be direected to those 'Free Parking' sites. The 'new' proxy servers were the greatst rubbish I have ever encountered. They were not only ad jammed, they were pop up jammed. So many ads would be arriving on the computer, some of them were those hideous full page ones, that I was deleting with both hands.
Secondly, the majority weren't CGI. This means that I could get to a page, but I couldn't do anything on it. I would click on a link and nothing would happen. It is one thing to go to a site, another thing to interact with that site.
Thirdly, the few that were CGI, Common Gateway Interface, (not AVATAR) took forever to load, (allegedly) and did not allow me to interact with the site.
To put it simply, if you want to go to Facebook but it is blocked, you want a proxy to unblock it. You want to be able to enter your username and password and get onto the site to read your messages or leave messages, or whatever you do on the site. If the proxy doesn't allow you to log in, what is the use?
Finally I found a functioning Proxy; Kproxy. This is what a Proxy Server is supposed to be. It is supposed to be a simple interface between you and the computer you want to access.