The ability to tag resources with uncontrolled metadata or "folksonomies" is often characterized as one of the central features of "Web 2.0" applications. Folksonomies are said to support emergent classification, where the semantic value of the tags and their relation to one another is worked out through a negotiated process of users applying their selected tags and seeing what others have tagged the same way. Few studies exist to show how folksonomic tagging is actually done, and to what extent users share each other?s tagging patterns. In this paper, we present the results of a social network analysis of two months worth of tagging Internet video on the social bookmarking system del.icio.us. The analysis reveals that specific videos are tagged in fairly coherent ways by a relatively tight group of users. However, contrary to our expectations, there does not appear to be much re-use of tags across different content, or even very many users tagging more than a few similar items. Overwhelmingly, specific clusters of tags and users are associated with individual video links. This result suggests that tagging bookmarks is highly local, and the overall collection of tags is unlikely to result in a coherent globally navigable classification system.