These women share something beyond extending their brands to Discovery channels.
Both are masters of infotainment — which can be tricky footing. And each woman has sought to blend partisan politics and celebrity — in a mirror image of the other.
Winfrey brought her talk-show super-stardom onto the 2008 presidential campaign trail, when she stumped for Barack Obama. Palin, in the obverse, is bringing her campaign magnetism and flair for partisan politics to the small screen
But as Winfrey could probably tell Palin, politics and entertainment are not a natural fit.
The most jarring thing about Palin's debut last week on Fox News' inspiration-heavy "Real American Stories with Sarah Palin" wasn't the content, but the spectacle of Palin hosting such a hope-y, change-y show.
Just a week before, she was at a tea party rally — slamming Obama, chiding the media and issuing dire warnings about America.
The result? It didn't matter that "Real American Stories" was apolitical puffery. Entertainers like LL Cool J didn't want anything to do with it, apparently fearful of Palin's polarization.
Meanwhile, "Sarah Palin's Alaska," billed as a documentary free of partisanship, has already triggered an outcry from some environmental groups, upset about Palin's support of aerial wolf hunting.
Like Palin, Winfrey was effective on the campaign trail, drawing huge crowds and big media attention for Obama in the early days of his presidential run.
One study claimed that she was responsible for netting the Illinois senator more than 1 million votes during the early Democratic primaries — enough to make the difference between winning and losing.
But even as Winfrey did her best to keep politics out of her daytime show, her popularity slipped, her ratings fell and comments on her Website were full of critical, even nasty, messages, questioning her judgment and motives.
She's still the dominant face of daytime talk, and her retirement from her show had long been a possibility. But there are doubts about whether she can extend success to a 24-hour network.
Now these women's roles are reversed. Winfrey inspired endless chatter about her ability to play kingmaker in politics — a role she has long played for her talk-show subjects. Her choice of a book, for example, creates a best seller.
Palin's test is the mirror image — if she can spike ratings in the same way she stirs political passions.
It's a big "if." Her debut on "Real American Stories" had only average ratings. While she's certainly able to bring a ready-made following to "Sarah Palin's Alaska," she has yet to prove that she can extend that to be an enduring talk-show presence --- in other words, the next Winfrey.
But if Winfrey pulled back from partisanship, Palin shows no sign of straying from it.
Palin has thrived, says Janice Peck, author of "The Age of Oprah," in a time when politics has been "de-politicized" -- free from serious policy discussion. "It becomes all about image," said Peck, "Palin epitomizes that."
Palin's ability to bring a built-in fan base is no small thing with Balkanized TV audiences. But television success in the long-run is about more than overcoming partisanship.
"It's a skill set that involves being authentic," said Jim Paratore, who as president of Telepictures oversaw "The Ellen DeGeneres Show" and "The Rosie O'Donnell Show," -- comfortable and compelling, day in and day out. And doing your homework.
Doing homework is not something Palin thrives on, according to "Game Change" John Heilemann and Mark Halperin's book about the 2008 presidential campaign.
And moving into infotainment can be complicated. Only after many years did George Stephanopoulos jump from the Sunday talk show "This Week" to the frothier "Good Morning America."
In the late 1990s, former Rep. Susan Molinari worked as co-anchor of "CBS News Saturday Morning," but the leap from campaign trail to cooking segment proved too great.
In Palin's case, Paratore says, "She'll get sampled, but the question is, 'What happens on week six or week 12?'"
Palin also won't be able to escape TV's version of polling, the "Q" score. Henry Schafer, executive vice president of Marketing Evaluations, the Q scores company, says that though they don't measure politicians, Palin has become enough of a TV figure to warrant research -- probably starting this summer.
Schafer's measurements can be unforgiving. His company spotted the dip in Winfrey's likeability, and the ascendancy of DeGeneres. Viewers' emotions, Schafer explains, "are driving program choices more than ever before."
Palin herself knows where she stands, even if she may not be entirely aware of what's ahead. "Oprah, you're the queen of talk shows," Palin told Winfrey, when appearing on her show last November, "There's nothing to ever worry about."
Actually, in the world of infotainment, there's anxiety aplenty.
Ted Johnson is deputy editor of Variety and blogs at Wilshire & Washington.