folk·son·o·my 
(fōk-sŏnə-mē′)
(fōk-sŏnə-mē′)n. pl. folk·son·o·mies
A collection of metatags generated by users of a particular website that together create a taxonomy that categorizes the content of that website.
[Coined in 2004 by Thomas Vander Wal, American information architect, as a blend of FOLK and TAXONOMY.]