They thrive by mining the private information of the billions of people who use them, many of whom are naïve about the value of what they are giving up with each post or click. But the companies are grudging at best when it comes to being open about themselves.
Their tendency to show more reserve than the people whom they have encouraged to offer up bits of personal data has been especially striking in recent days.
The Rose McGowan episode was a case in point. After the actress posted a series of tweets suggesting that entertainment and media executives had helped cover up allegations of sexual harassment and abuse against Harvey Weinstein, Twitter shut down her account. Soon after that, the hashtag #WomenBoycottTwitter started trending, and Twitter reactivated it. That was followed by an unsurprising apology, in which Twitter's chief executive, Jack Dorsey, said there was a need to be more "transparent" in explaining how Twitter comes to such decisions.
Last month, the Facebook founder Mark Zuckerberg invoked "transparency" when he took to Facebook Live to say the company would share more information about who buys political advertising on its platform. His vow followed Facebook's admission that it had allowed a shady Russian outfit close to the Kremlin to buy ads — in rubles! — that were apparently meant to divide the country and tilt the presidential election.
With each repetition of the "transparency" talk from the big social media platforms, more people begin to see right through it. I wonder if members of the House and Senate intelligence committees will do the same when the platforms' top executives testify at the upcoming hearings on Russians and the election, assuming they show up.
Maybe the flaw in the social-media matrix lies in the whole concept of "transparency," anyway. The tech companies and their visionary founders have raised it as the cure-all for oppression and corruption — even as a path to personal enlightenment.
"The days of you having a different image for your work friends or co-workers and for the other people you know are probably coming to an end pretty quickly," Mr. Zuckerberg told the author David Kirkpatrickin 2009. "Having two identities for yourself is an example of a lack of integrity."
As Mr. Dorsey told Wired in April, "A more open exchange of information is our purpose, and it's a noble one."
The social-media overlords seem sincere when they describe their high-minded intentions. They talk much less, however, about the money they make from their users' relinquishment of privacy.
The willingness of those who make daily use of Google and social media sites to offer up their likes and dislikes, not to mention the details of their spending habits and internet wanderings, provides Mr. Zuckerberg and his fellows with the personal data that is the holy grail of modern advertising. It also gives them an endless stream of free content to put those ads beside. Their users' endless posts, spats and vacation pics make for the ultimate reality show.
At times, social-media feeds are about as authentic as a standard reality show, too. Witness last week's story about the former Fox News anchor Jane Skinner Goodell, who is married to Roger Goodell, the commissioner of the National Football League. Turns out she was using Twitter to attack journalists whose work was critical of her husband, but, as The Wall Street Journal reported, she was doing so through a fake persona with a laughably unimaginative pseudonym, "Jones smith."
Ms. Goodell's use of an online disguise suggests how hard it is to be yourself on social media, and the recent experience of the ESPN host Jemele Hill shows even more clearly the perils of mixing private and public personae on Twitter.
ESPN and its parent company, Disney, initially gave Ms. Hill a pass for violating their social media guidelines when she used Twitter to call Mr. Trump a "white supremacist" after his equivocation over the deadly rally in Charlottesville. The Disney chief Robert A. Iger said he respected her urge to speak out as a black American.
Then she used Twitter to call for a boycott of the Dallas Cowboys' advertisers after the team's owner, Jerry Jones, said he would bench players who kneel in protest during the national anthem. ESPN noted this had been Ms. Hill's second violation. But let's face it, this time she was going after ESPN's bread and butter.
My newspaper is also dealing with the question of how transparent a person should be on social media. On Friday, it announced a new policy for its journalists requiring them to avoid say anything on the platforms that they could not say under the banner of The New York Times. At a TimesTalks event in Washington on Thursday night, The Times' executive editor, Dean Baquet, said that overly opinionated or partisan tweets could undermine the paper's mission of reporting "objectively and clearly."
Pointing up the new tension between journalists' speaking freely and being part of a team at a news organization like The Times, the White House correspondent Peter Baker noted that the Trump administration "doesn't make a distinction" between his tweets and those of his colleagues who do not cover politics.
More from The New York Times:
In some cases, candor can seem too much for the platforms themselves. At least, that's what Ms. McGowan, who received a settlement from Mr. Weinstein in 1997 after she said he assaulted her, accused Twitter of last week.
Twitter suspended her account as she was posting messages singling out people who, in her view, had enabled Mr. Weinstein to harass and abuse a long line of women. (She went on to write in a Tweet that Mr. Weinstein had raped her; Mr. Weinstein has denied all allegations of "nonconsensual sex.") Twitter only made things worse for itself when it said it had temporarily shut down Ms. McGowan's account because she had violated its "terms of service" by sharing someone else's personal phone number.
That drew a round of angry tweets from Twitter users who seemed ready for the moment with examples of apparent terms-of-service violations that went unpunished — including a few by none other than the president of the United States.
A Twitter spokesman didn't respond to my email asking if it had an answer to these critics, which is what I should have expected.
Facebook's chief operating officer, Sheryl Sandberg, seemed to break from the social-media chiefs' habit of avoiding the press last week when she sat for an interview with Mike Allen of Axios, with which Facebook has brokered a deal for several exclusive interviews. As Mr. Allen wrote, the session marked the first public interview with a senior Facebook executive since it had revealed the Russian ad spree.
The Axios deal struck me as less than ideal for a company claiming it wants to be transparent. Why not open up the floor? (In a statement on Facebook, the company's vice president of policy and communications, Elliot Schrage, offered a crumb, saying that Facebook would start working with "other news outlets and independent groups wanting access to our executives.")
Then again, Ms. Sandberg was ready to share only so much. "Things happened on our platform that shouldn't have happened," she said, before dodging Mr. Allen's question about whether Facebook noticed any overlap in those targeted by the Russian and Trump advertising campaigns.
Maybe, I figured, she or Mr. Zuckerberg would share more on their Facebook pages. I clicked my way over to them — alas, no such luck.
I was tempted to express my displeasure by leaving behind orange frowny faces — but then I remembered our new social media policy and stepped away from the keyboard.
Commentary by Jim Rutenberg of The New York Times.