No, this is not the Search solution, but a identity management solution. The best definition online I could find is:
Active Directory Federation Services (AD FS) is a feature introduced with Windows Server 2003 R2 that provides an identity access solution. It gives browser-based clients, which are inside or outside your network, Single-Sign-On (SSO) access to web-based applications. It is important to note that AD FS only works for web-based applications. AD FS can be used in web hosting or SharePoint environments. It is very useful when a company has web servers located in a DMZ or at a remote hosting vendor or business partner and wants to control account credentials to their web applications from the internal Active Directory.
This is some seriously cool stuff. You can basically link your AD with the AD of a supplier, customer or other business partner so people can log in. And the best part is, you can also use this with SharePoint! I can already see myself using this next time I have to design an extranet for a customer.
link love on how to set up AD FS:
1. Overview and installation
2. Configure IIS to use SSL on the FS servers
3. Configure the FS certificates
4. Configuring the FS server in the Account domain
5. Configuring the FS server in the Resource domain
6. Creating the federation trust on both sides