It seamlessly integrates with other Google Apps.
However it seems to be only launched for Google Apps? Which is continuing the confusion about the separation between my Google Apps for My Domain and my FREE primary Google Account which I use heavily.
In addition it isn't available in my current Google Apps for my domain. I had to sign up for a new account with a domain I had laying around to get at it.
A little frustrating, but I am still excited to play with. I will be working with it and see what I can get done.