This solution uses Active Directory to manage authentication for customer sites and site collections. This approach makes it easy to use the Microsoft Provisioning System (MPS) to create service offerings and to provision Windows SharePoint Services version 3.0 sites.
Customer users can sign in to the Windows SharePoint Services site through other means because Windows SharePoint Services version 3.0 allows for a range of authentication methods to be used for SharePoint sites and site collections. In order to use forms-based authentication methods, you will need to develop a Web application that makes use of ASP.NET pluggable authentication modules and integrates with the Windows SharePoint Services version 3.0 membership provider. For more information, see Plan authentication methods.