GIVEN THE GLACIAL STATE of change in daytime TV, it’s easy to take for granted the enormous influence Oprah Winfrey wields over her adoring audience. Yet with the talk host preparing to expand her empire, it’s worth contemplating her genius — along with the dubious enterprises she promotes in waging her feel-good, self-help crusade.Consistently dominant by day, Oprah (a first-name talent if there ever was one) is preparing a viral-like spread into primetime, with two specials in the next week — one tied to the Oscars, the other showcasing her good works in Africa — and a pair of reality TV series on the drawing board, all for ABC. It’s the daytime program, however, that remains her power base, and last week she used it as a forum for two highly questionable discussions — featuring TV psychics John Edward and “Medium” inspiration Allison DuBois, and then a follow-up regarding “The Secret,” which boils down to a semi-mystical theory that putting forth positive energy (good vibrations?) will bring positive things back to you because “like attracts like.” Presiding over each hour, Oprah endeavored to at least appear neutral. “This is a show that lets you decide for yourself,” she said at the outset of the psychic episode. “We’re not trying to tell you how to think about anything.” Um, bull. Because no matter how she couches it, in both instances Oprah provided an approving, wholly uncritical platform to what could be the equivalent of modern-day snake-oil sales. In that respect, her run-in with James Frey, the fabulist whose memoir “A Million Little Pieces” turned out to be mostly fiction, wasn’t a complete anomaly. And while she was rightfully credited for setting the record straight by bringing Frey back after endorsing his book to pummel him on air, it’s hard to imagine a similar act of contrition over the Secret or psychics barring an equally damning revelation. OPRAH’S RIGHTEOUS INDIGNATION over the Frey affair was clearly meant to label the vetting lapse as an aberration, as opposed to being symptomatic of more general gullibility. Watching her gush over the Secret and present testimonial after testimonial embracing the psychics, though, the prevailing sense is that Frey was simply an unskilled huckster who happened to get exposed. In both of those hours, moreover, Oprah allowed guests to misleadingly place the imprimatur of “science” on psychobabble, without the vaguest challenge from another authority figure. (Frustrated, I had to watch an episode of Penn & Teller’s myth-debunking Showtime series “Bullshit!” just to keep from losing my lunch.) Instead, the host listened intently as two gurus who teach “The Secret” served up easy-to-swallow soundbites seemingly tailored for rehab sessions and greeting cards. “Stop trying,” Secret teacher James Arthur Ray counseled cheerily. “Trying is failing with honor. … Don’t try.” Barring the correct usage of grammar, Yoda could have easily delivered the same affirmative lesson minus the cloying smile, as in “Try not; do, or do not. There is no try.” TELLINGLY, THE SECRET’S PEDDLERS cleverly sought to indemnify themselves against criticism, with Ray saying, “Mediocrity always attacks excellence.” Not surprisingly, Oprah eagerly embraced this concept, which is hardly necessary: She’s virtually immune to second-guessing at this stage, and no amount of naysaying (negativity?) from such an obvious mediocrity as a TV critic can slow, much less derail, the gravy train. There’s no questioning, either, that Oprah is truly excellent at what she does — the Rolls-Royce among daytime talk’s used-car lot, which admittedly amounts to damnation with faint praise. The larger issue is that she frequently offers facile answers to people sitting home at 3 o’clock who might actually have serious problems — the kind that can’t necessarily be dispatched with a little positive thinking. What we don’t see on the show, perhaps mercifully, is the inevitable letdown in those instances when the self-help guidance and pithy catchphrases fall flat. Oprah has clearly set a glorious personal example by elevating herself from humble beginnings to media royalty, but as she continues to help herself, too often it involves lending that formidable, hard-won brand name to ventures and personalities that should be approached with caution and skepticism. That’s her (dirty little) secret.