The Merck Group uses Process Observer in the context of Master Data Harmonization. While the core process of creating and changing master data is implemented using SAP Master Data Governance (SAP MDG-M, find the Success Story here), Process Observer is used for reporting and to make the process visible. A story about this was released at the SAP Forum in Austria 2013, DSAG Technologietage 2013 and at SAP TechEd in 2012. The presentation from the SAP Forum is online and can be reviewed here (the document is available in German only).
The basis for the integration of Process Observer into SAP MDG is the SAP Master Data Governance rapid-deployment solution. In the SAP Demo Store, a demo is available showcasing this integration: EIM MDG-M Create Material with Process Observer (Logon to the SAP Demo Store required).