80 Personal Content Experience: Managing Digital Life in the Mobile Age 18 fundamentally better ways. For a brief introduction to metadata, see Baca (2000). This chapter introduces metadata through several concrete exam- ples, and discusses its relation to mobility and an inherently related topic, context-awareness. We especially emphasize the consumers, as opposed to the professional content producers often assumed in metadata-related texts. We present the benefi ts metadata brings to the users, and analyse potential threats of its excessive usage. We also briefl y investigate existing metadata solutions, and discuss some impor- tant technologies that are needed to support effi cient metadata pro- cessing. Finally, we discuss interoperability and related efforts in this area, by considering both devices and applications. 4.1 Metadata for Consumers: A Brief Introduction The modern world is said to be in the middle of an information explosion, the data available on the Internet increasing exponentially. However, this not new, as we have been there before – as early as the 15th century. When the technology for printing text en masse became widely available, new ways were needed to manage the explosive growth in the available information. In the days of Gutenberg, the information was stored in a physical form. Today the content is digital, but many of the ways for organizing text-oriented material remain the same. The library institution was born out of the need to manage large physical collections of information. To effectively manage a large col- lection of books, libraries have developed an access system for storing the books in a way that enables people to browse them (Figure 4-1). In some cases, browsing book spines is fi ne, but if you wish to fi nd a certain book quickly you need a better technique, for instance, some kind of classifi cation. In a typical library, you will see bookshelves laid out according to some organizational principle. The shelves will show markings that indicate the category of the books contained, and also you will notice that the books in the categories are organized based on a certain sort key. The classifi cation mechanism is used to index books in order to 18 Others also consider metadata important. Try typing “metadata is * important” (including quotes) in google and witness the wide variety of interest areas that benefi t from metadata.