SharePoint Hosting Services : Windows SharePoint Services (WSS) currently in version 3 provides all the objects underpinning all Microsoft SharePoint Hosting technology. WSS is provided as a free download from Microsoft for Windows Server 2003 Service Pack 1 or later and is added to the Microsoft .NET Framework. WSS 3 is an object model for creating web pages and developing web based collaboration, document management, and content publishing. WSS is only provided for Microsoft servers and cannot be deployed on any other OS. One can also upgrade to a low cost dedicated SharePoint server with hyper-v hosting.
At the time of this writing WSS is in its third release from Microsoft. WSS 3 is the framework that underlies Microsoft Office SharePoint Server 2007. WSS 2 was the framework beneath SharePoint Portal Server 2003.