Tip 20: “Papers Please!”, or SharePoint Extranet Authentication
This tip is for Windows SharePoint Services 3.0 and Microsoft Office SharePoint Server 2007.
Did you know that you have many options available for account storage and authentication in extranet scenarios in SharePoint by using Forms Based Authentication?
Here is a list of just some of the different account stores you can leverage.
ASP.Net SQL Provider, Active Directory, Active Directory Application Mode (ADAM), Active Directory Lightweight Directory Services (AD LDS), LDAP stores from many 3rd parties or you can write your own.