As passengers shot video Sunday of a man screaming as he was dragged from his airplane seat, the gears of social media started turning violently against United Airlines and an industry that has almost unlimited power over its paying customers.

The posted video has gone viral, and in the process, outraged consumers flexed muscles, yet again, that did not exist a mere decade ago.

“What congressman wouldn’t want to be on the side of airline passengers right now?” asks Lawrence Glickman, professor of American studies at Cornell University.

What was first an unsettling viral video shot in Chicago on a Louisville, Kentucky-bound plane has become a public relations debacle for United. The company's stock lost about $250 million in value Tuesday, and the Department of Transportation, responding to the incident, says it's opening an investigation.

Over two days, United Airlines CEO Oscar Munoz shifted his tone from offering a clipped, almost sterile, written statement about the incident to one on Tuesday that expressed concern for the well-being of the passenger.

"I continue to be disturbed by what happened on this flight, and I deeply apologize to the customer forcibly removed and to all the customers aboard," Munoz said in a statement Tuesday afternoon. "No one should ever be mistreated this way."

The man who was removed, reportedly identified in a statement by his lawyer as David Dao, a Louisville-area doctor, was one of four passengers United wanted to bump to make room for its employees. Three passengers begrudgingly walked off. But Dao refused, saying he had to get back to his patients. Airport security was called to remove him.

On the video, a passenger can be heard pleading with security not to hurt Dao, and then gasping when she sees blood on his face. Other passengers also shot smartphone videos. The drama streamed out within moments to shape public opinion.

The airline says Dao was chosen at random to surrender his seat. He had no redress because passengers have fewer rights than they might realize when they buy tickets and fly.

A decade ago, consumers didn’t hold as much sway. They could write complaint letters, post negative reviews, contact the Better Business Bureau, or take their beef to a lawmaker. Results, never guaranteed, would be slow to come.

But today, with smartphones to capture incidents of alleged customer mistreatment, and with Twitter and Facebook instantly amplifying for multiple millions of viewers, the open marketplace has become vastly more treacherous for merchants of all stripes and sizes. 

"The key with social media is to get the issue rolling,” says Robert Mayer, professor of family and consumer studies at the University of Utah. “The more the problems are exposed, the more it will ripple through the marketplace, and the greater the chance that companies or the government will do something."

Some CEOs and industry representatives have pointed out that social media posts often present incidents out of context and can unfairly tar a company or brand. Some who post, they say, might be inflating otherwise small incidents out of proportion because of personal grudges or for financial gain.

Mayer notes that the United Airlines incident followed a few rough days for Delta Air Lines, which was hit by weather-related delays in Atlanta that stranded thousands of passengers.

"There's a lot of consumer ire at the airlines industry, and people feel more vulnerable because of the consolidation," he says. "The United video has made consumers aware that they don't have the rights to their seats they may have thought they had. I can't help but think that there will be changes as a result, perhaps in the compensation for overbooking."

The flight was not technically overbooked but completely sold out. United decided that it needed volunteers so that four employees could have seats to make it to Louisville to work on another scheduled flight the same night.

Many of the United critics on social media, no doubt, have suffered hassles at the hands of airlines.

The possible motivation to join the chorus of voices? Even if you can’t get satisfaction, on social media you can at least get some revenge, and perhaps even a measure of control over corporate America.

But Susan Grant, director of consumer protection and privacy at the Consumer Federation of America, says consumers should use social media judiciously for it to be most effective. 

"Consumers have more channels at their disposal than ever before to stand up for their rights,” she says. “Commerce is an engine of power, and people should take advantage of these tools."

But "you can’t blow up every small incident. If you’re treated unfairly, I strongly suggest you speak up and let the company know what you think," she says. "If you can’t get the problem resolved, then using social media is a good option.”

How the Message Makes a Difference

The recent United video isn’t the first time the airline has found itself in consumers’ crosshairs. Just two weeks ago there was a backlash after a passenger noticed two teenage girls were denied access to a flight for wearing leggings—standard attire for teens and others. The passenger tweeted about it. The tweets were shared and became viral. Celebrities, including Chrissy Teigen, weighed in on the seemingly sexist policy.  

In 2009, United suffered another PR mishap that resulted in a composed song critical of the airline.

Musician David Carroll was traveling with two guitars, one of which he said the airline damaged despite being protected in a hard-shell case with extra protective padding. Carroll alleged $1,200 of damage.

He says he asked United Airlines for months to take responsibility, but he was never satisfied.

So he wrote a song, “United Breaks Guitars,” that told his tale of woe with a country rhythm. Then he shared the video with a few hundred Facebook friends.

The song reached a million views within four days and kept growing.  

Carroll turned the attention into a book called "United Breaks Guitars: The Power of One Voice in the Age of Social Media." He also launched a global speaking career.

Carroll sees similarities between his experience and the recent outrage. “It’s what I went through times 10,” he says. In some ways he believes that because of all the social media noise, it’s more difficult to get a message through today. “But if it does get through, it catches on like wildfire,” he says.

“Maybe the bigger organizations need to feel the pain a little bit before they do the right thing for the right reasons,” Carroll says. “Now that people are so connected and something like this can blow up in your face so quickly, companies need to incorporate compassion a little bit more. There’s profit in that. It’s a good business decision to make.”

Correction: This article previously said United's stock lost $500 million in value Tuesday. In fact, it lost about $250 million in value.