The Microsoft SharePoint Products and Technologies protocol documentation provides detailed technical specifications for Microsoft proprietary protocols (including extensions to industry-standard or other published protocols) that are implemented and used in SharePoint Products and Technologies to interoperate or communicate with Microsoft products.
The documentation includes a set of companion overview and reference documents that supplement the technical specifications with conceptual background, overviews of inter-protocol relationships and interactions, and technical reference information.
Microsoft is implementing four new interoperability principles and corresponding actions across its high-volume business products: (1) ensuring open connections; (2) promoting data portability; (3) enhancing support for industry standards; and (4) fostering more open engagement with customers and the industry, including open source communities.
Read the full Microsoft PressPass article: http://www.microsoft.com/presspass/press/2008/feb08/02-21ExpandInteroperabilityPR.mspx
SharePoint Products and Technologies Open Protocols Introduction
Microsoft makes available information about protocols, binary file formats, and other specifications for a number of its most popular products, including various versions of Windows and Windows Server, Microsoft SQL Server, Microsoft Office, Microsoft Exchange Server, and Microsoft Office SharePoint Server. These technical specifications enable and encourage a vibrant development community, resulting in smarter, interoperable products.