This document provides an overview of the SharePoint 2010 Managed Metadata Service. It defines metadata and taxonomy, and explains that a managed metadata service allows terms to be organized hierarchically in term sets. The document describes how term sets can be global or local in scope. Keywords are also discussed as an unmanaged tagging system. The document outlines the main applications of the managed metadata service: 1) taxonomies using term sets, 2) folksonomies using keywords, and 3) syndicated content types that can be published from a hub site collection.