Richard Poynder ,June 11, 2008

May 13, 2008, Dempsey proposes 4 sources of metadata:

1. Professional: The curatorial professions have made major investments in knowledge organization, through the development and application of cataloging rules, controlled vocabularies, authorities, gazetteers, and so on.
2. Contributed: A major phenomenon of recent years has been the emergence of many sites which invite, aggregate and mine data contributed by users, and mobilize that data to rank, recommend and relate resources. This data includes tags, reviews, ratings, further details, and so on.
3. Programmatically promoted: We are handling more digital materials, where it is possible to programmatically identify and promote metadata from resources themselves or groups of resources. We will also do more to mine collections, including collections of metadata, to discern pattern and relations. We are increasingly familiar with clustering, entity identification, automatic classification and other approaches.
4. Intentional: I have used this term to refer to the data that we are collecting about use and usage. Pagerank is based on aggregate linking choices. Amazon recommendations are based on aggregate purchase choices.