In any case, beyond the love of MSM folks at sounding very, very deep analyzing pop culture, there are were a number of pretty interesting stories about Oprah impact on American religious culture. I know that within my own family (who are mostly LCMS) there has been at least some religious impact. I was at a relative's house a while back and actually saw a Eckhart Tolle book! My goodness!
Anyways, what most people said about Oprah is that she sort of combines the culture of the black church and New Agism. From the black church, she takes the idea of political/personal redemption from victimhood/redemptive victimhood. Also her emotionalism and idea of autonomous self-reliance. Put succinctly, stuff you find in American Revivalism. From New Agism, she takes her universalism (remember, she was at Yankee Stadium!) and her mystical-amorphous concept of the divine.
What I find interesting about all this is that it seems to me to be a sort of synthesis of the two streams of thought in American religious culture. More or less, they broke apart during the 18th century and didn't really ever come back together again.
What must be understood about American religious culture is that it is fundamentally Reformed. For the early Reformed theologians, natural theology and the autonomy of human reason didn't have the bad wrap that it did in the Lutheran reformation. To oversimplify a bit, the Reformed theologians keep and expanded on the older Thomistic metaphysics of the high Middle Ages (think Thomas Donelly's famous article "Thomistic Calvinism"). Lacking the supernatural authority of the Church as the older tradition had, Reformed theologians combined this natural theology with a highly individualistic concept of the certainty of revelation and redemption. How do I know I'm elect? You just know, said Calvin in the first edition of the Institutes (1536). In the later editions, Calvin focused on the signs of election (good works, faith, participation in the sacraments). Later the Puritans leaned very heavily on a personal conversion experience. Often they would not let people receive communion or be official church-members if they couldn't give a public account of their conversion experience!
In the 18th century, this synthesis broke apart. You see the results! The Founding Father all believed in the Unitarian/Deistic God of Reformed natural theology- as did Lincoln, FDR, Reagan, Obama, etc. The common people and the modern mega-church goers all believer in the interior, spiritual, emoting, redeeming God of the camp meeting. Of course, the Unitarian/Deist types also gave rise to plenty of mysticism themselves in the form of the transcendentalist movement. But this quasi-pantheism wasn't all that different than New England Unitarianism in it's concept of the ethical life or the amorphous God that gave rise to it.
This brings us back to Oprah. What's interesting is that she is able to combine together the two models of the redemptive camp meeting God, and the mystical, aloof, transcendent God. Perhaps because she embodies these two tendencies in American religious life, she appeals to everyone? Or perhaps there not really all that different models of God! Notice, neither side would want to confess with Luther in the Great Confession Concerning the Lord's Supper (1528): "There is no other God than the man Jesus."
It's an interesting suggestion and worth exploring!