June 23, 2018, was a momentous day in the online life of Laura Pittenger, a New York playwright with roughly 1,200 Twitter followers. That was when the actor John Cusack, who has more than 1.6 million followers, retweeted her and followed her back.
Ms. Pittenger was happy to have a celebrity follower. Then came the anxiety.
“Honestly, I had a moment of paralysis,” Ms. Pittenger said. “I thought, ‘Why would he follow me?’ I was basically a nervous wreck that he was following me at all.”
Mr. Cusack, whose three-decade career has included starring roles in “Say Anything,” “High Fidelity” and “Hot Tub Time Machine,” followed Ms. Pittenger after she said, in a tweet, that the two of them shared a fondness for the antiwar activist Daniel Berrigan. Mr. Cusack had used a Berrigan quotation in his Twitter bio, Ms. Pittenger noted, and she had quoted the same line on her Facebook page.
But a relationship that started sweetly came to an abrupt end on Feb. 7, when Mr. Cusack posted a tweet critical of Representative Alexandria Ocasio-Cortez, Democrat of New York, and Ms. Pittenger replied in defense of the congresswoman.
Within hours, Ms. Pittenger said, Mr. Cusack blocked her, leaving her confused.
“He followed me for no reason and he blocked me for no reason,” she said. “I’m not going to campaign to get him back.”
When asked about what had happened, Mr. Cusack said he did not recall blocking Ms. Pittenger.
“I wouldn’t go out of my way to block someone who knew of Daniel Berrigan,” he said.
He explained that Twitter bots had swarmed his account, as they do from time to time, attacking him for his political views. “They say, ‘You stink,’” he said. “‘Your movies stink.’ ‘You are a Communist.’”
He added that he must have nixed Ms. Pittenger when he went on a blocking spree meant to purge the bots.
“Sometimes people get swept up in that,” Mr. Cusack said.
Some people make sport of wrangling celebrity followers. In a podcast interview, Naomi Fry, a writer for The New Yorker, described her successful attempt to get the singer John Mayer to follow her on Twitter. “I begged and I begged and I begged,” she told the hosts of the “Public Announcement” podcast. “He heard the clarion call.”
Celebrities, for their part, have been known to unilaterally pluck followers from obscurity. In 2010, Conan O’Brien announced that he would follow only one person on Twitter, Sarah Killen, then a 19-year-old student from Michigan. “It’s totally nuts,” Ms. Killen said at the time.
Nine years later, she remains the sole follow for Mr. O’Brien, who has roughly 29 million followers, and she now has nearly 415,000 Twitter followers of her own.
It’s not just a Twitter phenomenon: celebrities have caused users of Instagram and Facebook to swoon from an unexpected follow too. While most people welcome having a famous follower, the online relationship between those with disparate levels of social-media status can lead to a feeling of self-consciousness in the followee.
Meryl Cooper, an author and publicist, said she thinks frequently of her most notable follower, Barack Obama, who has more than 105 million Twitter fans. Although Ms. Cooper’s Twitter account is one of more than 600,000 followed by the 44th president, she still felt proud when he followed her in 2016.
“He is my most prized follow,” Ms. Cooper said. “It would be hard to top that.”
And when hackers busted into her Twitter account last November, her first thought was of Mr. Obama.
“I didn’t know what crazy thing these hackers would say,” she said. Would they post something inflammatory? Would they send a rude message to 44? Her fears did not come true during the tense time that she monitored the account until it was back in her control. To her relief, Mr. Obama has remained among her 1,749 followers.
“I do not kid myself that he knows who I am,” Ms. Cooper said. “But there are bragging rights to having the former leader of the free world follow you.”
Two years ago, April Glick Pulito, an actor and bartender with more than 800 Twitter followers, won over the director Joss Whedon when she posted about subscribing to Slate magazine and other publications in a tweet that ended with “#resist.”
After a retweet from the Slate account, Mr. Whedon, the director of “The Avengers,” followed her. At the time, Ms. Glick Pulito recalled, he followed only 235 people. She followed him back.
“I didn’t want to be an over-excited fan girl,” she said. “I wanted to play it cool.”
Ms. Glick Pulito said she would not have said hello to Mr. Whedon if she saw him dining at a restaurant. Was following him back the digital equivalent?
“I was conscious of him following me, absolutely,” she said. “I’m a little ashamed to admit it, but I check weekly to see if he is still following me.”
Last September, Ms. Glick Pulito got married. As a joke, she posted a tweet inviting her celebrity follower to the wedding. Mr. Whedon did not come. But he did send her a direct message on Twitter, wishing her a happy honeymoon and life.
“I’m a cautionary tale, but enjoy,” he wrote. (Mr. Whedon was involved a messy divorce in 2016.)
Despite having never met Mr. Whedon in person, Ms. Glick Pulito said she felt a sense of responsibility to him.
“I feel weird talking about it, because it is so personal,” she said. “If he unfollowed me after this, I would feel like I betrayed him.”
