Social bookmark tools are rapidly emerging on the Web. In such
stems users are setting up lightweight conceptual structures
lled folksonomies. The reason for their immediate success is the
ct that no specific skills are needed for participating. In this
per we specify a formal model for folksonomies, briefly describe
r own system BibSonomy,
ich allows for sharing both bookmarks and
blication references,
d discuss first steps towards emergent semantics.