It’s hard to describe MOSS 2007 and Windows Sharepoint Services to people. Helpfully, Microsoft has released a VHD (a virtual disk that can be loaded on Microsoft Virtual PC or Virtual Server 2005 R2) with a pre-configured MOSS 2007 installation. That’ll give you an idea of what Sharepoint and Microsoft’s collaboration solution is all about.
"Microsoft Office SharePoint Server 2007 is an integrated suite of server capabilities that can help improve organizational effectiveness by providing comprehensive content management and enterprise search, accelerating shared business processes, and facilitating information-sharing across boundaries for better business insight. Office SharePoint Server 2007 supports all intranet, extranet, and Web applications across an enterprise within one integrated platform, instead of relying on separate fragmented systems. Additionally, this collaboration and content management server provides IT professionals and developers with the platform and tools they need for server administration, application extensibility, and interoperability".