annotating individual parts of an image or specifying a particular closed user group, e.g., relatives who attended the last family gathering. The most innovative function is tagging: Tagging makes it possible to add keywords, or tags, to other users’ images. By means of these usergenerated tags, a collective taxonomy—or folksonomy, a neologism created out of «folk» and «taxonomy»—is produced which continuously generates new image-sorting criteria. This function is particularly useful for auditory and visual data, as these keywords, which are fixed and assigned only once, are difficult to find, and a full-text search string, which directly addresses the semantic units, cannot be adapted. Unlike in a traditional archive, here the classifications are neither consistent nor are they clearly assigned to the objects, rather they are expandable and, above all, variable. Wolfgang Ernst has pointed out that for electronic databases, the term «archive» only functions in a purely metaphorical way: «[T]he twenty-first century will be the century beyond the archives.» [24] In the intensely advertised «twenty-first century,» dynamic or variable keyword lists for accessing digitally recorded images that do not exist

outside electronic systems take the place of ‹still› images, which can be located in flat file cabinets by means of systematic catalogs. This means that the images do not necessarily have to be stored or maintained as an object; it is possible that they merely circulate within electronic devices and networks, where they can also disappear. However, the immateriality of digital image data is relative, because the data are based on a considerable arsenal of hardware, which generates the ‹live experience› in the first place.

On Flickr, the most popular tags range from «africa, amsterdam, animal» and «family, february, festival» to «winter, work, yellow, zoo.» They designate an object, a place or the time of year of the photograph, or, as is the case for colors, an atmospheric impression in the broadest sense of the word, a mood. Even the variety of keywords does not cause their redundancy to collapse. This also applies to the images themselves. There are 21,690 photographs retrievable using the tag «cats,» and one has the impression that one is not looking at the images for the first time. The series of images might just as well be an ironic turn of the