The current architecture of the web gives the server sole responsibility for determining the content that results from a browser's request. Because of the well-defined information stream between browser and server, this architecture is easily extended to allow multiple entities to cooperate in producing the final delivered content. Applications can then be built as intermediary components which live along the information stream. WBI defines intermediaries which can observe, produce, and edit web content anywhere between browser and server. WBI provides a place for applications to manipulate web content. These applications can be used for personalization, protocol extensions, collaboration, advising, and dynamic content generation. The same concepts can be applied to non-web information streams, such as mouse/keyboard input, information push, and e-mail.