When someone wishes to add a new skos:Concept, either as expertise, related to a publication, whatever, they are given a list of four vocabularies, and searches for concepts go against the four vocabularies:
AGROVOC (Agricultural Vocabulary)
GEMET (GEneral Multilingual Environmental Thesaurus)
LCSH (Library of Congress Subject Headings)
UMLS (Unified Medical Language System)
Should make these modules that can be added if desired but not built-in by default.