Scott Sumner has a long and thoughtful post. Here is one bit:
According to the Official Method, none of these tidbits matter. But I have noticed that they have had some impact on my readers. They are each slightly persuasive about some aspect of my argument.
It has to be read in the context of the longer post, but it's a very important point. And this:
So that’s the goal of my blog, to constantly use theoretical arguments, empirical data, clever metaphors, and historical analogies that make people see the current situation in a new way.
Read the whole thing. It's one of the best statements of how blogging can make a difference; just don't call Scott a blogger…