High-performance Web Proxy Server. WebDoubler is a high-performance Web Proxy Server, designed to increase Web browser performance, improve security, and enable various filtering functions for small, medium, or large workgroups. WebDoubler runs on Mac OS computers and offers a Mac-like, simple administration interface and transparent client operation. The WebDoubler package is made up of two primary component types. The \\core\\ application includes the graphical user interface, Web \\listener\\ and an extremely robust API. Virtually all other functions are performed by \\plug-ins\\ that are written as separate modules that perform tasks using the WebDoubler API. Advanced cache management, PICS content filtering, and even basic HTTP file retrieval are all implemented as plug-ins.