PUBLIC MARKS with tags SKOS & metadata

SKOS Core provides a model for expressing the basic structure and content of concept schemes such as thesauri, classification schemes, subject heading lists, taxonomies, 'folksonomies', other types of controlled vocabulary, and also concept schemes embedd

Strictly speaking, this would be a 4th way of organising stuff, somewhere between a taxonomy (categorized) and searchable (indexed). It’s not a taxonomy because one item can have multiple free-text tags, and it’s not straightforward indexing, because it is information ‘outside’ the item (meta-information), and not part of it.

"SKOS (Simple Knowledge Organization System), recently introduced by the W3C, is a model for expressing knowledge organization systems in a machine-understandable way, within the framework of the Semantic Web".

binding RDF and tags with SKOS

flickr is used to describe things which are related to Flickr at http://flickr.com/ an online sharing photographs service.