The so-called Web 2.0 brought a new breadth to the Internet, and a social perspective that seems set to stay. Services such as LinkedIn, Hi5, and Facebook have found a place in our society. People connect to each other through common paths. Meta-APIs such as Google's November 2007 release, OpenSocial, enable social applications to operate across multiple sites and services, providing a way to relate much of this data. In social bookmarking tools (e.g., Connotea, Bibsonomy), and media sharing services (such as Youtube, Flickr, Picasa, Slideshare) people are asked to tag and otherwise annotate and share their resources inside communities or at a global scale, creating a huge amount of user generated metadata (tags) with a clear value for information discovery.This workshop intends to gather all interested in such applications and developments, and in their relationship with metadata and practices. The themes of the workshop will be:-Emerging trends in social tagging.-Tagging communities and Web-based collaboration.-Web standards for resource description in collaborative landscapes.-Vocabulary building from folksonomies (tag-ontologies, tag-thesaurus, etc.)-Metadata and annotation management.-Formats for describing communities (FOAF, SIOC, etc.)-Analysis of online communities (SNA) through folksonomies and tagging systems.-Other ways of describing information for Web 2.0 (microformats, etc.)A description of the workshop formatThe workshop will include invited talks and presentations, giving a consistent background for discussion. This will be followed by short presentations or position papers submitted by interested researchers, bloggers, etc. that will be evaluated by the Program Committee (see below). The Call for Presentations will be sent to discussion lists from different perspectives and backgrounds, including the DC Social Tagging Community, microformats- and other related communities.A discussion on improving communication between (and thus research within) different user-generated metadata communities will be included. This last session in the workshop will be conducted ‘BridgeCamp’ style.(BridgeCamp grew from the Barcamp movement, in which participants in the workshop are offered an essentially unfilled timetable in which to either propose questions, offer to give a 5-10 minute presentation answering them, with a further 10-5 minutes for discussion. Several members of the Program Committee have considerable experience with this style of workshop and have found it to be a valuable addition to a traditional set of presentations, providing a structure more readily oriented to outcomes relevant to the participants than normal ‘breakout sessions’).