NetWeaver is an application builder from Netweaver for integrating databases and business processes from some sources while exploiting the leading Web services technologies. Part of the company's mySAP product group that can run on a single instance of NetWeaver known as SAP Web Application Server (SAP WEBAs).
The benefit of using Netweaver is you can access SAP data using the web (http protocol) or even mobile. Thus you can save on costs involved in training users on SAP Client-side GUI.
