“Collaborative tagging seems to address a real need on the Web as demonstrated by the growing popularity of tagging and annotation sites (see del.icio.us, flickr, technorati, RawSugar, Shadows, etc.). The most popular sites already have a combined user base of several millions. The philosophy of what is called Web 2.0, the social Web or also the two-way Web is that users can and should be content creators as well as consumers and it suggests that there is a great deal of untapped potential for tagging to improve how web content is organized, navigated and experienced. Yet it is not yet clear how it will evolve and how it will scale, when, if at all, its usage base will go beyond early adopters. The goal of this workshop is to bring researchers and practitioners together in order to explore both the social and technical issues and challenges involved in Web tagging. We plan to address not only the current state of collaborative tagging, and understand its attractiveness to early adopters but also discuss its future.” (W3 Tagging Workshop)