InfoWorld: Microsoft delivers SharePoint Services for Windows Server: October 01, 2003: By : Platforms "
Microsoft Corp. on Wednesday delivered Windows SharePoint Services, a part of Windows Server 2003 that allows end-users to set up Web sites for collaboration and information sharing.
The release of Windows SharePoint Services follows five months after Windows Server 2003. It ships later because of tight integration with Microsoft's Office System products, said Mike Fitzmaurice, technical product manager at Microsoft. Office 2003 is shipping to some customers, but will be officially launched on Oct. 21."
This is a big one, albeit kind of a weird launch (it's free and it's part of Windows Server 2003, despite the different GA dates); see this overview for my perspective on why WSS is important.