Can you give me an introduction to SAP NetWeaver?

Can you give an introduction about SAP NetWeaver, ITS, BSP and SRM? What are the relationships between these?

NetWeaver is the common name for all the later products by SAP AG, basically saying everything that is not R/3 is NetWeaver. ITS (Internet Transaction Service) used to be a Web server proxy to allow Internet access to an SAP system. ITS is now integrated in the SAP WAS (Web Application Server) and is only used as a proxy for the SAPGUI for HTML. BSP (Business Server Pages) is SAP's version for dynamic Web pages written in the SAP WAS, in analogy to Microsoft ASP (Active Server Pages) and Jave JSP (Java Server Pages). SRM is Supplier Relationship Management and it is the NetWeaver module for procurement.