Very interesting Claire.

I think this is where our idea of the book's purpose differs.
I saw Freakonomics as giving insight to a revolutionary economists ways and methods. It introduced the reader to Levitt's unconventional way of viewing the world.

I do not see it as a source of actual information (although the information presented is valid and generally unknown). I thought the examples provided were intended to act as examples to Levitt's style of economics-- more along the lines of "look at what I can prove using my mind and some numbers!" as opposed to "Here is some valuable information I derived from this data." I see it as an examination of the means, the way he got to those answers, rather than an important report of content. The range of topics was so broad and unconnected that Dubner/Levitt could not have been hoping to inform the reader of the things Levitt derived, but merely teach a new way to see things.
Lets not get caught up in the content; focus on the rhetoric, the structure of economics.
Its structure not information.

If it was information they were hoping to provide, I should think that the organization and content would have indicated so. (The organization of examples is better suited to explain the use of economic tools than to enlighten the audience of the dangers of different things.)

Levitt's organization:
I. "My style of economics is unconventional"
a. random tidbit of information derived from my unconventional style of economics.
b. another, unconnected tidbit of information derived from my style of economics.
c. a slightly more connected (to example b) tidbit derived from my style of economics

and so on for several chapters. If he was informing he would have to have a thesis, and unifying theme (which he himself states his book lacks), etc.