Why not Squid or mod_proxy?
Both Squid and mod_proxy are great for reducing the load on web servers, and we encourage everybody to use them. The disadvantage of these caching proxies are that they only work “vertically”, i.e., they reduce the bandwidth downstream from the originating web site to the users’ browsers. That web site still gets 1 download per (non-cascading) proxy. The FreeCache system works more “horizontally”, i.e., FreeCaches fill themselves up from neighboring FreeCaches if at all possible. Hence, the load on the originating web site is much lower. FreeCache and caching proxies are complementary technologies. Both can be used to reduce the impact on web sites.
