As a tableau it is becoming ever more familiar: the disgraced politician flanked by family members in various states of humiliation or anger, as he tries to explain away his moment of madness.

Last week it was the turn of the New York mayoral candidate Anthony Weiner, mortified wife by his side. He faced the media at a press conference to concede that, yes, the engorged private parts displayed in images on TheDirty.com website were indeed his. Yes, he'd sent the pictures under the pseudonym Carlos Danger to Sydney Leathers, 22, who had criticised his politics but become a raunchy sexting partner. Yes, they were sent months after he'd resigned from Congress in 2011 after a similar relationship was exposed and at a time he was supposedly working on his marriage. No, he could not recall know how many other women were out there. Perhaps as many as 10.

In many ways, this salacious, self-inflicted political scandal of 2013 mirrors another, earlier in the internet age. In 1998, Matt Drudge's Drudge Report scooped Newsweek magazine with news of Monica Lewinsky, her thong and her semen-stained dress in Bill Clinton's Oval Office.

Fifteen years on, and with a public accustomed to the technology of "sexting" and "selfies", Weiner's indiscretion was revealed by TheDirty.com, a new type of news website that not only elevates the risk of exposure faced by public figures but also threatens to usurp established media by trading in salacious exposure.

TheDirty.com is the brainchild of Hooman Abedi Karamian, aka Nik Richie, a former pop promoter on the fringes of celebrity, from Scottsdale, Arizona. He says he was approached by Leathers, from Indiana, with the now notorious images sent to her by Carlos Danger, aka Weiner. Leathers told Richie that Weiner had reneged on a promise to buy her a property in Chicago and said she would release the pictures as proof he had not changed since a series of similar relationships had derailed his career two years ago.

The Dirty's innovation is to marry the attributes of YouTube, which largely relies on user-submitted material, with those of popular celebrity and entertainment sites such as TMZ or Radar.

"A lot of the girls who come to us are fame-chasers," he told the Observer. "So they sleep with athletes and celebrities then submit their or their friends' hook-ups to site." Since it's all "third-party" content, Richie is protected from libel by the provisions of the US communications decency act: "Now everyone can have a platform to express their right to freedom of speech to say what they want about whomever they want."

He sees The Dirty as a natural media evolution given that social media has already rendered the concept of privacy irrelevant. "There is no such thing as privacy. The internet has taken over the right to privacy. Look at Facebook or Craigslist. Look at Twitter. People have to put themselves out there to get jobs. The moment you go on the internet, you are a public figure, and we live in a society where people want to brag about the things they do to people they don't even know."

While that may be hard to accept, it may go some way to explaining the disconnection between the political class, the media and the public over Weiner. Until the new revelations, he was surging in the polls. Still, the establishment political wisdom was that his candidacy was an aberration, a joke. "These kinds of stories are so commonplace now that people just don't care about it," said Richie.

Professor Mark Sachleben of Shippensburg University, Pennsylvania, who contributed to the 2011 book Sex Scandals in American Politics, concurs. He sees an evolution in the political sex scandal.

Fifty years ago, the press overlooked politicians' indiscretions. Then, with greater press appetite for the exposure of public misdeeds after Watergate, private shame demanded public humiliation. Then came Bill Clinton.

"Everybody knew Clinton was a whore-dog," Sachleben says. "It wasn't that people weren't disappointed when Monica Lewinsky came along, but the vast majority of Americans shrugged because they knew what they were getting into."

The internet, social media and websites specialising in scandal have made it far more likely for the behaviour of political figures to be detected, he says: "It's almost impossible to have a private life where you could hide something like this."

At the same time, he says, there are signs that the public is weary of being outraged at the behaviour of elected officials. Studies suggest that candidates caught up in sex scandals typically lose about 5% of the vote, and rehabilitation after a scandal is now relatively rapid. "It depends on the prevailing political culture, the resources and wider support of the politician in question," Sachleben says. But Weiner, he points out, has neither Clinton's political record nor his charisma.

Still, successful political rehabilitation is becoming more frequent. In June 2009, South Carolina governor Mark Sanford vanished for six days. Aides said he was "hiking the Appalachian trail". He resigned when it emerged that he has been visiting his mistress in Argentina. This year, South Carolina voters elected Sanford to Congress.

He managed his political comeback without the support of his wife, who had divorced him. Weiner's political chances, by contrast, appear more dependent on the continuing support of his wife, Huma Abedin, a long-time Hillary Clinton aide, in mirroring Mrs Clinton's stand-by-your-man response to her husband's original Gennifer Flowers "bimbo eruption" of 1992.

But if Abedin hadn't stood by her man, his alter-ego Carlos Danger might already have destroyed Weiner's campaign. New polls detect "redemption fatigue" among Weiner supporters. But at campaign stops, voters – many of them women – were still keen to hear his message about a better deal for the middle class.

In New York's permissive political culture, being a tainted candidate is preferable to being a nondescript one – and the field of candidates to replace Michael Bloomberg is widely regarded as weak.

Neither is Weiner, by choice or accident, the only candidate making sexuality a theme. His closest rival is Christine Quinn, a lesbian and Bloomberg's successor of choice. Quinn recently published a memoir about being a recovering bulimic and alcoholic that the New York Times says is not selling well. When Weiner failed to swiftly admonish a voter for referring to Quinn as "the dyke", the backlash was slight. Another candidate, Bill de Blasio, promotes his black, former lesbian wife as an aspect of his progressiveness.

On Thursday, Weiner could not say for sure how many women or lewd images might yet surface. He denied being a sex addict, but said he was seeking professional help for his behaviour. Despite the predatory aspect of Carlos Danger's activities, voters appear unwilling to condemn sexting, which is enjoyed by 32% of 18-to-34-year-old men and 25% of 35-to-44-year-old women. Snapchat, the popular self-deleting messaging app, is almost designed for it.

Unlike Drudge, who never claimed to be neutral in the Lewinsky scandal, Richie says his interest in the Weiner-Danger-Leathers affair was apolitical: "I'm from California, I don't care about New York politics. The reason we have freedom of speech is to expose these stories. The mainstream media, even sites like TMZ, don't want to take the risk. With me it doesn't matter. I'm still small enough. I can give people the voice they don't have."

But is there a larger point to make? Yes, says Richie: "We can make choices. You can become infamous on the internet or you can say: I'm not going to make an Anthony Weiner-type mistake. You think you can live a private life, but you can't. If you don't want scandal, don't put your picture on the internet. There's no good in the end result."