SAP E-Mail Response Management System (ERMS) was introduced with CRM 4.0 Service Industries Extension back in 2004. At the time, I published a configuration guide, which can still be found in SAP Note 940882. However, as the years passed and the ERMS solution was enhanced, some of the information in the original guide needed to be updated. Thankfully, Amrish Singh helped me out by updating and enhancing my original configuration guide with his new enhanced and extended ERMS Configuration Guide for SAP CRM 7.0.
You can find the above updated guide as well as all other relevant ERMS-related information and collaterals here in my Jul 20, 2015 blog post, ERMS Configuration Guides and Documentation“.