An interesting twist to the proxy cache approach is the notion of reverse proxy caching, in which caches are deployed near the origin of the content, instead of near clients. This is an attractive solution for servers or domains which expect a high number of requests and want to assure a high level of quality of service. Reverse proxy caching is also a useful mechanism when supporting web hosting farms (virtual domains mapped to a single physical site), an increasingly common service for many Internet service providers (ISPs).
Note that reverse proxy caching deployment is totally independent of client-side proxy caching. In fact, they may co-exist and collectively improve Web performance from the user, network, and server perspectives.