In 2003 SAP released the SAP .NET Connector (NCo) to enable communication between the .NET platform and SAP systems. The first NCo versions (1.0x, 2.0) were aimed at .NET 1.x (with support for Visual Studio .NET and later on VS 2003), and it remained at that level. This resulted in the overall conclusion that the NCo was considered 'dead', or at least strongly outdated (Future Support of NCo). This idea was re-enfored in May 2009 by 1) the advice of Juergen Daiberl to use webservices or WCF Lob Adapter in favor of NCo, and 2) a statement of SAP's Rima Rudnik-Sirich phrasing that 'ES Explorer is a successor of NCo'.
However, the truth (or weakness) of SAP Enterprise Services is that currently only a limited set is available, supporting a restricted subset of the SAP business processes functionality. There are alternatives to custom develop SAP/MS intergration whenever it is not standard provided: WCF on SAP webservices, WCF BizTalk Adapter on SAP BAPIs and RFC. And forthcoming is Duet Enterprise, with a positioning for interoperability and collaboration between SharePoint 2010 and Office 2010 clients towards SAP processes and data.
And now SAP apparently decided to give new life to the NCo proposition. They have announced .NET Connector 3.0, to be released in December 2010. At first, this appears strange when you combine this announcement with the upcoming release of Duet Enterprise. However, Duet Enterprise is thus strictly scoped for interoperability between SharePoint plus Office 2010 and SAP environments. A renewed NCo will provide an additional alternative to communicate from other .NET application formats (e.g. WPF, WF, Services) to the SAP systems.