Polipo is a small and fast caching web proxy (a web cache, an HTTP
proxy, a proxy server). While Polipo was designed to be used by one
person or a small group of people, there is nothing that prevents it
from being used by a larger group.

Polipo has some features that are, as far as I know, unique among
currently available proxies:
  * Polipo will use HTTP/1.1 pipelining if it believes that the remote
    server supports it, whether the incoming requests are pipelined
    or come in simultaneously on multiple connections (this is more
    than the simple usage of persistent connections, which is done by
    e.g. Squid); Polipo will cache the initial segment of an instance
    if the download has been interrupted, and, if necessary, complete
    it later using Range requests;
  * Polipo will upgrade client requests to HTTP/1.1 even if they
    come in as HTTP/1.0, and up- or downgrade server replies to the
    client's capabilities (this may involve conversion to or from the
    HTTP/1.1 chunked encoding);
  * Polipo has complete support for IPv6 (except for scoped
    (link-local) addresses).
  * Polipo can optionally use a technique known as Poor Man's
    Multiplexing to reduce latency even further.

In short, Polipo uses a plethora of techniques to make web browsing
(seem) faster.