Sorry Matt, but i don't buy it. There are many places, where your links can be put in a spammy environment and theres no way, you will get rid of them, until the blog or other type of site won't cease to exist. Google made it possible to attack the competition and manipulate the rankings even more than before (you just have to know how to do it properly). Now they tell us their fairy tales. After Penguin here in Poland a new market has emerged immediately. There are many new companies in the Google rankings, which offer to attack your competitors with spammy links.