I aggree its totally awesome. I am going to start using the stuff as soon as the new sites are up.
I think the secret to the book that is not mentioned is as usual relevant content. It's fine having all this promotion but if no-one will be interested in what you have to say then you will be wasting a great deal of time, energy and money (lost).
So market testing if you are thinking of exploiting a niche is xrucial to your success.
John.