We describe a new messaging system, designed to transparently send media (video, presentations, animations, audio, interactive games, still images, 3D spaces, or combinations thereto) to other users across the Internet. Unlike previous Internet communication systems (Web, email, IM), the MediaMessenger incorporates all code and media types as first class objects; unlike previous media systems, the MediaMessenger offers rich mixed-media spaces, hyperlinked through a system of portals. In addition, the MediaMessenger exhibits a pure peer-to-peer unrooted namespace, explicit authorizations to send and receive messages (and thus prevents unwanted messaging, or spam), and blends the features of both electronic mail and Web browsing.