A major fraction of digital information is stored in file systems. File systems organize files usually in labelled directory trees and provide a minimum support for user-driven file annotation, linkage and categorization. Although file systems play a major role in knowledge organization, both in enterprise contexts as well as in the personal information sphere, they have rarely been considered in web-based information integration. To a large extent, this can be contributed to the limited metadata support of file systems and to the lack of stable identifiers for file and directories, which makes it hard to expose these objects in a global web.