What does it mean to "run SAP?" Historically, to run SAP meant that the SAP application R/3 was installed and used by business users. For years, the SAP R/3 application was synonymous with SAP. They were one and the same, and to say you ran SAP was the same thing as saying you ran R/3. R/3 was SAP's first true client/server-based online transaction processing (OLTP) system—a system that by its very nature satisfied day-to-day transactional needs like you've read about this hour. Like its mainframe predecessor R/2, within R/3 was a number of business modules, such as Finance, Logistics, Human Resource Management, Warehouse Management, and more. SAP ERP is the successor to R/3.
So today when you hear people say they are running SAP, be sure to ask them what that really means in their specific case—with so many different products and solutions out there bearing the SAP label, it's not a good idea to assume anything. Sure, SAP's most popular product remains ERP. However, a lot of older SAP R/3 systems are still running, and even more SAP SCM, CRM, PLM, and SRM systems are out there.