After 25 years, Oprah Winfrey’s daytime talk show is coming to end, and she’s moving to cable. This powerful woman — who was born into poverty in rural Mississippi, and rose to become one of the wealthiest people in the world — has left her mark on the business world and in the mass media. Oprah is at the top of her game. She has transformed commercial television programming, and has had a lasting impact on the black community and American popular culture in general.

Now is the perfect time to ask, what would a world without Oprah look like? What if Oprah never existed?

Without Oprah, we would be deprived of one of the nation’s most profound success stories, and a role model for women everywhere. She came from a hard life, born to a single mother and the victim of childhood sexual abuse. Oprah was sent to juvenile detention at 13 and became a teen mother at 14, with her premature baby dying in infancy. And yet today, with her Harpo Productions, she has built a media empire worth an estimated $2.7 billion.

Click here to view a Grio slideshow of Oprah’s most memorable hairdos

Perhaps it was despite the adversity she experienced — or even because of them — that she flourished by building a brand name on positivity. “I never wanted to be in a position again in life where I was meant to do something but couldn’t do it because somebody was telling me I couldn’t,” Winfrey told writers at Harvard Business School for a case study they prepared on her business enterprises.

Along with BET founder Bob Johnson, Oprah is only one of two African-American billionaires ever listed in the annual Forbes roster of the richest people in the world. Now, she is the only African-American on that list, one of a just a handful of black billionaires in the world. Time magazine named Oprah among the 100 most influential people of the 20th century, while Newsweek named her the most important person in books and media.

If Oprah never existed, psychology would not be as accessible to the public. The key to Oprah’s success has been in her ability to capitalize on a “confession culture” in which people bear their souls to the public. Oprah is credited by many for creating the public space that allows people to “tell all” on a range of personal matters that were once shrouded in secrecy and considered taboo, including sexual abuse. For good or for bad, she was the trailblazer when it came to giving public figures and celebrities a forum to express their feelings in front of a prime-time audience. And that is Oprah’s enduring legacy to popular culture.

Moreover, with Oprah sharing her own personal travails regarding abuse, relationships, body image and other issues on the TV screen, she has shown by example that you can “come clean” without fear of stigmatization or criticism. All the while, she has connected with fans on a personal level by showing compassion and empowering her audiences, in spite of her staggering wealth and immense fame. It is fitting that Maria Shriver — who recently announced her separation from former California Gov. Arnold Schwarzenegger, in light of him having an affair with their maid and fathering a son a decade ago — is one of Oprah’s final guests.

Television programming would be different in a world without Oprah Winfrey. Before she came on the scene, there were assumptions concerning what a television show host was supposed to look like. She broke barriers, and served as a living example to African-Americans, women and others that you can succeed in a world where you do not necessarily fit the mold.

“Nobody had ever seen anybody like me,” she told the Chicago Tribune of her early years in broadcasting at WLS-Channel 7 in the early 1980s. “They just couldn’t figure it out. I wasn’t pretty. I wasn’t even slim. I didn’t sing. I had no qualities that anybody could understand.”

With 6 million viewers a week, Oprah’s talk show ranks fifth for syndicated programs on network television. Even a powerhouse such as Ms. Winfrey faced competition from cable, with 12.6 million viewers two decades ago. This reality explains her transition to that media format. “I love this show,” Winfrey said. “This show has been my life. And I love it enough to know when it’s time to say good-bye.”Although Oprah bids farewell to the program that made her a pop icon and a media mogul-diva, we will continue to feel her presence as a commercial success. Commercialism has become a different animal under Oprah, as the Oprah brand has few rivals, if any. With her personality-branded book club, she brought attention to otherwise obscure books. And when Oprah anoints a book through inclusion in her book club, that author should expect an additional 1 million in sales.

In other words, she literally turns books into gold. Nielsen reports that in the past decade, Oprah has sold over 22 million copies of books under her Book Club branding. After the talk show host selected A New Earth, a title by self-help author Eckhart Tolle, the book sold 3.4 million copies. In addition, the Oprah paperback edition of James Frey’s A Million Little Pieces sold 2.7 million copies, and her edition of Cormac McCarthy’s The Road sold 1.4 million copies.

Click here to view a slideshow of the 25 greatest guests

That’s a lot of ink, and a great deal of paper, both white and green. Some observers suggest that she singlehandedly saved the publishing industry — a degree of financial success attributable to Oprah’s business savvy, influence and appeal.

And her branding extends to other products beyond publishing as well. Oprah’s “favorite things” are the perfect example of product placement, if not a more effective form of infomercial. Plus, she provides a more-than-willing customer base in the form of her ardent followers. For a corporate marketing exec, this is what the Promised Land looks like. Just one example is DreamTime’s Foot Cozys, a brand of aromatherapy slippers, which had sold 3,000 pairs a month, but jumped to 20,000 a month after it was featured on an episode of Oprah’s show in 2002.

However, the commercial success of the Oprah “brand” is due to far more than merely her television show and branding. The Oprah empire also consists of O, the Oprah magazine, a monthly publication with a circulation of around 2.5 million, her startup OWN cable network, and Harpo Productions, the TV and film production company known for The Great Debaters and Tuesdays with Morrie.

Although criticized for not being too controversial and not speaking out on certain issues such as abortion, gay rights or national health care — which actually may have contributed to her success — Oprah has spoken out and given back to the community. After 9/11 she reached out to the Muslim community and fought against prejudice with antiwar programming, and programs on Islam. And the black community is better off with an Oprah Winfrey among us.

For her, giving back has meant far more than bestowing lavish gifts on her audience members. For example, with a $12 million donation to Morehouse College in Atlanta, Winfrey is the largest individual donor to that historically black institution. Her original goal of putting 100 men through Morehouse was increased to 1,000. Moreover, Oprah’s commitment to educational opportunity extends beyond the boundaries of the U.S., with her 22-acre Oprah Winfrey Leadership Academy for Girls near Johannesburg, South Africa. The school’s mission is to “provide a nurturing educational environment for academically gifted girls who come from disadvantaged backgrounds.”

A number of people have managed to ride on Oprah’s coattails. As a kingmaker and queenmaker, so to speak, she has acted in the best tradition of those individuals who get to the top and bring others up with them. Oprah is responsible for creating celebrities in their own right, such as best friend and syndicated talk show host Gayle King (host of the Gayle King Show on OWN TV and formerly on Sirius XM), Dr. Phil McGraw, the Emmy-award winning Dr. Mehmet Oz, designer Nate Berkus and her personal trainer Bob Greene. In the absence of Oprah, these people would not be famous.

And then there’s Stedman Graham, the former basketball player and public relations executive who was once engaged to Winfrey and has been dating her for more than 25 years. Their “spiritual relationship” has long been the subject of gossip, and Graham, an Oprah fixture, has been the butt of jokes for his relationship to Oprah. If you go to Urban Dictionary and type in the words “Stedman Graham,” you will find the word “freechoader,” which is defined as “A boyfriend who lives with and sponges off his girlfriend who works her fingers to the bone to support him.” For example, “K-Fed is the biggest freechoader since Stedman Graham.”

Finally, perhaps the most well-known and powerful beneficiary of Oprah’s kingmaking abilities is the president himself. Specifically, the media mogul endorsed Obama for president in 2008 when he was still considered a longshot, and she raised money for his campaign. Her ratings apparently took a dip because of her open support of Obama, and she received criticism in the media for the move, though it doesn’t seem to have hurt her in the long term.

Meanwhile, according to some economists, the endorsement made a difference for Obama in the Democratic primary against Hillary Clinton and in the general election, giving him as many as 1 million extra votes in the former. This time around, she reportedly will not publicly endorse Obama in 2012 out of fear of alienating some of her OWN viewers.

Now how’s that for a world without Oprah?