We describe a new approach to fission of multimedia information based on the concept of active documents advertising on the Internet, whereby a document dynamically builds metadata, joins a group of documents of the same interest and advertises the collected metadata to the members of the group. This abstraction of metadata is called an adlet, which is the core of our approach. This approach supports the visual specification and visualization of adlets, the creation and composition of adlets, the negotiation protocols and communications with the active network. Two important features make this approach applicable to applications in multimedia information fusion, information retrieval, data mining, geographic information systems and medical information systems: (a) any document, including web page, database record, video file, audio file, image and even paper documents, can be enhanced by an adlet and become an active document; (b) any node in a nonactive network can be enhanced by adlet-savvy software and the adlet-enhanced node can co-exist with other non-enhanced nodes. An experimental prototype provides a testbed for feasibility studies in a hybrid active network environment.