That religion can be big business is not news to anyone. But this Zenit analysis by Fr. John Flynn is an especially good synopsis of the current state and size of the “Christianity market” in the United States.
On a roughly related note, I’ve been meaning to mention the creation of a new blog on faith and business: the Business as Mission Network blog run by Justin Forman. It tracks news in the “business as mission” movement, which envisions businesses, especially within predominantly non-Christian regions, as instruments of evangelization.