Reading Francisco's post, I'm struck by the notion of the lowest common denominator. It seems like the lowest common denominator of humanity is precisely that which applies to all human beings: our incompleteness and our desire. And properly understood, each desire we have is nothing less than a temporal manifestation of our ultimate desire for the infinite, for Christ. The very thing that makes Christ attractive is that He appeals to the lowest common denominator of humanity, our primal needs and desires.
The problem with Oprah's cult, sexy commercials, and nutrigrain is that each takes that desire and directs it towards an incomplete and unfulfilling end. The desire itself that each taps into, the desire for the infinite (manifest in spirituality, in sex, and feeling great) is fundamentally good. The reason each appeals to any kind of common denominator at all is because each appeals to our fundamental desire for the good. But they redirect us to an unfulfilling end, an end that won't fulfill those desires. Those things gives us a incomplete solution to the fundamental problem of our humanity, which is why each of them leaves us, in the end, feeling isolated and incomplete. But the problem is not that they appeal to the lowest common denominator, but its that they appeal to it without giving any real solution or fulfillment.