Some classic Master Data examples are customers, products, suppliers, employees, locations and accounts. Platon defines MDM as the “structured management of Master Data in terms of definitions, governance, architecture, technology and processes”.
MDM is about:
- Having an enterprise focus on data quality.
- Having common business definitions (Meta Data) for Master Data.
- Ensuring adequate Master Data to support business processes.
- Securing business driven Data Governance and accountability for data quality.
- Ensuring appropriate maintenance processes around Master Data.
- Ensuring integration of Master Data across the system landscape.
- Ensuring relevant standards, compliance and GDS across value chain.
MDM involves the entire system landscape including all operational and analytical systems where Master Data is used, created, updated or deleted. It also includes the platform for sharing and synchronizing Master Data with trading and collaboration partners.
You can find more information in Platons
Master Data Management brochure 
and in Platons
GS1 Global Standards Services brochure