http://i2peek-a-boo.i2p/dr_who_faq.html
The clients then
ask the proxy to fetch the objects they need (web pages, images, movies etc) on their
behalf, and when the proxy has done so, it hands the results back to the client. There are many reasons to use web proxies, such as firewalling (security), caching
(efficiency) and others, and there are just as many different proxies to accommodate those
needs.