a multi-purpose application level gateway, or a proxy server which runs on multiple platforms (Unix, Windows, MacOS X and OS/2). DeleGate mediates communication of various protocols (HTTP, FTP, NNTP, SMTP, POP, Telnet, SOCKS, etc.)
an application that uses the power of Google's global computer network to make web pages load faster, local cache, prefetching, data compression. Currently a Google Labs product. (probably good for very slow connections and as a general proxy)