Proxy Server:A proxy server is a kind of buffer between your computer and the Internet resources you are accessing. The data you request come to the proxy first, and only then it transmits the data to you.Proxy servers accumulate and save files that are most often requested by thousands of Internet users in a special database, called “cache”. Therefore, proxy servers are able to increase the speed of your connection to the Internet. The cache of a proxy server may already contain information you need by the time of your request, making it possible for the proxy to deliver it immediately.Security and privacy. Anonymous proxy servers that hide your IP address thereby saving you from vulnerabilities concerned with it. Sometimes you may encounter problems while accessing to web server when server administrator restricted access from your IP or even from wide IP range (for example restricting access from certain countries or geographical regions). So you try to access those pages using an anonymous proxy server.
Public Proxy Server:It is a proxy server which is free and open for everybody on the Internet. Unfortunately most of them are not anonymous.Free service trying to provide list of public HTTP proxy servers. Usually provide small list of proxies with low percent of functioning servers due to hosting restrictions on CPU time (they simply can't allow themselves to check many proxies every second especially in parallel).