What is the best practices method of cross enabling applications with forms authentication?

I understand that to authenticate across applications, you configure machinekeys, and other items to be identical.  But in doing that, I see that it is "oudated" according to the following URL.http://msdn.microsoft.com/en-us/library/ms998288.aspx

The link is nice enough to tell me it is outdate, but not nice enought to tell me the new preferred way?

Can someone point me that direction?

Thanks