"They are built to be human-usable (...) are targeted primarily for storage/retrieval of personal information and serendipitous discovery of group information . (...) The development communities for each are abuzz with ideas for exploiting the structure"
"The future co-existence of controlled vocabularies and collaborative tagging is predicted, with each appropriate for use within distinct information contexts: formal and informal."
Tag Systems "are supremely responsive to user needs and vocabularies (...). (T)ransforming the creation of explicit metadata for resources from an isolated, professional activity into a shared, communicative activity by users is an important development"
"TagOntology is about identifying and formalizing a conceptualization of the activity of tagging, and building technology that commits to the ontology at the semantic level."