Dean claims that it's unnatural for conservatives and libertarians to accept the idea of corporations. I think he's wrong. While he may have moral argument, it is of no practical value.
My point: there may be rational moral arguments against corporations, but they are as pointless as moral arguments against thinking bad thoughts. Without the security of a stock or bond and the protection of arms-length ownership, few intelligent people would invest in individuals who have what might be a good idea. Before the concept of the corporation, the world was agrarian and lacke even large farming interests. Corporations are the cornerstone of modern wealth accumulation, and no reasonable substitute has been offered.
UPDATE: Here's an interesting link that mostly supports Dean's view, but provides good information all around.
UPDATE: Dean's post now has 32 comments, most of which are very thoughtful, intelligent posts. This is a thread worth saving, and I encourage you to take a look.