Editing Image sharing (section)

===Image classification===
Image sharing sites usually propose several ways to classify images.<ref>Brown, F. (2007). "[http://www.allegrotechindexing.com/metadata.pdf Metadata Goes Mainstream] {{Webarchive|url=https://web.archive.org/web/20070616124934/http://www.allegrotechindexing.com/metadata.pdf |date=2007-06-16 }}—about online photo galleries and the lessons we can learn."</ref> Most sites propose at least a [[Taxonomy (general)|taxonomy]] where images can be grouped within a directory-like structure in so-called "galleries". Some sites also allow users to classify images using tags to build a [[folksonomy]]. Depending on the restrictions on the set of users allowed to tag a single document and the set of tags available to describe the document, one speaks about narrow and broad folksonomies.<ref>Vanderwal, T. (2005). "[http://www.vanderwal.net/random/entrysel.php?blog=1635 Explaining and Showing Broad and Narrow Folksonomies] {{Webarchive|url=https://web.archive.org/web/20210610144214/https://www.vanderwal.net/random/entrysel.php?blog=1635 |date=2021-06-10 }}."</ref> A folksonomy is broad when there is no restriction on the set of taggers and available tags. When there are limitations, the folksonomy is called narrow. Another mechanism is coupling taxonomy and folksonomy, where tags associated to galleries and artists are cascaded to the galleries and artist's pictures. Broad taxonomies have interesting properties like the [[power law]].<ref>Speroni, Pietro. (2005-05-25). "[http://blog.pietrosperoni.it/2005/05/25/tag-clouds-metric/ On Tag Clouds, Metric, Tag Sets and Power Laws] {{Webarchive|url=https://web.archive.org/web/20061011212324/http://blog.pietrosperoni.it/2005/05/25/tag-clouds-metric/ |date=2006-10-11 }}." Retrieved 2016-10-23.</ref>