Windows SharePoint Services (WSS) is a free add-on for Windows Server 2003 for creating websites to provide document sharing and collaboration.
Windows SharePoint Services was a complete redesign of SharePoint Team Services (STS) WSS v1 and takes advantage of ASP.NET website technology. It originally used .NET 1.1, but can use .NET 2.0 with Service Pack 2. WSS 2.0 also provides a versioning system and stores files within the database rather than just on the file system.