Chapter 5: Realizing a Metadata Framework 181 *within* these domains. It is important, however, to also achieve “serendipitous” interoperability by being able to link (meta)data from different domains. Here, we should move beyond “rich metadata” to something we might call “connected metadata”. All this being said, we must emphasize the importance of the Semantic Web (Berners-Lee et al. 2001) and associated standards as a promising basis on which such cross-domain interoperability can be built. The Semantic Web represents a novel approach to interoperability: Whereas the “old” approach has been heavy, a priori standardization of *what* is being said in interoperable communication, the Semantic Web emphasizes the standardization of *how* to say these things, and leaves the defi nition of the seman- tics of the communication to not require a heavy, com- mittee-based standardization process. We can even envision “agents” that can acquire more information and *capabili- ties* (= semantic defi nitions, ontologies, etc.) as they go along and identify the need for such. Finally, I would like to share my pet metadata scenario: Imagine digital photographs that are subsequently anno- tated with rich, *connected* metadata (the annotation can in many cases happen more or less automatically: we already annotate images with a timestamp and possibly the loca- tion where the image was taken; ultimately the image metadata could include everything we know about the world at the moment the image was taken). Assuming the annota- tions indicate who the image depicts, the image is now connected to rich descriptions of people – these can come from the user’s own address book or may have been acquired from various social network representations (e.g., Friend- of-a-Friend, already a Semantic web-based schema). Assum- ing that the annotations indicate where the image was taken, a connection is made to any location information we might have (e.g., geographical ontologies and models). Finally, given that the image has a timestamp, it is con- nected to any other information that has a temporal extent (e.g., the user’s calendar). As a result, the metadata acts as “glue” that connects seemingly separate islands of information (people, places, and time). The image itself may now become less important than the metadata that it carries. Ora Lassila Research Fellow Nokia Research Center, Cambridge (Ora Lassila is a Research Fellow at the Nokia Research Center, Cambridge and a Visiting Scientist at MIT/CSAIL, working on Semantic Web and its applications to mobile and ubiquitous computing since 1996. Web: http://www.lassila.org/)