Chapter 5: Realizing a Metadata Framework 149 Mobile devices are used to create and enjoy content, yet due to limited storage capacity and reduced UI capabilities, content is rarely stored in a mobile device only. However, a mobile device is well suited for creating content, and accessing it while on the move. It is always with you and always con- nected. Therefore, with the help of context and metadata, a mobile device has all the potential to become a key device to content management. Due to the distributed nature of mobile content, the metadata we use to manage all our content must be separated from the content fi les and binaries. Even when content is stored in various places, in order to manage it we need to know what is available, where it is stored, and how to access it. All that information is metadata separated from the content itself. We need to start respecting metadata as the fi rst-class citizen that requires its own management tools and processes. Once we separate metadata from the content itself, some of the content management problems become metadata management problems. We need to ensure effi cient storage usage, how to keep metadata and its binary content data synchronized, how to handle different versions of meta- data, and how to maintain backup of metadata. Next, we will emphasize the importance of a system-wide metadata management solution over application-specifi c ones, as a means to solve or (at least mitigate) the issues discussed above. While the reason- ing behind this claim is discussed in detail throughout this chapter, in this section we will summarize the key requirements of metadata management framework as: • Provide a useful service for all content-intensive applications. • Remove redundancy in both metadata storage and management. • Aim at run-time effi ciency. • Allow future extensions to content types and metadata defi nitions. • Allow interoperability between applications, devices, and content types. • Support experiences by the means of cross-media relationships. A requirement for any system is to justify its existence. This means that we just cannot make a theoretically beautiful architecture. It also must work in real life and in all kinds of mobile devices with limited