Dymero - 9:46 pm on Sep 6, 2013 (gmt 0)
Did he leave something out?
Backlinks. Google knows all the connections between the sites. This churn method makes it pretty easy to find a network of sites that are set up very similarly, and which probably have a lot of low-quality posts. It's only a matter of using the first contact form to get a price for a guest post. Then the network is discovered. That it hasn't been targeted yet is only because it hasn't been found yet. But give it time and it will be.
Now that the basic process has been outlined here, you can be sure that Matt or someone on his team has taken note and will be looking for it.