What is Microsoft Windows SharePoint Services?

Windows SharePoint Services is the solution that enables you to create Web sites for information sharing and document collaboration. Windows SharePoint Services " a key piece of the information worker infrastructure delivered in Microsoft Windows Server 2003 " provides additional functionality to the Microsoft Office system and other desktop applications, and it serves as a platform for application development.
Office SharePoint Server 2007 builds on top of Windows SharePoint Services 3.0 to provide additional capabilities including collaboration, portal, search, enterprise content management, business process and forms, and business intelligence.