While the front-runners in the 2024 presidential race have yet to show up on Threads, the new Instagram app aimed at rivaling Twitter, many of the long-shot candidates were quick to take advantage of the platform’s rapidly growing audience.
“Buckle up and join me on Threads!” Senator Tim Scott, Republican of South Carolina, wrote in a caption accompanying a selfie of himself and others in a car that he posted on Thursday — by that morning, the app had already been downloaded more than 30 million times, putting it on track to be the most rapidly downloaded app ever.
But President Biden, former President Donald J. Trump and Gov. Ron DeSantis of Florida remain absent from the platform so far.
And that may be just fine with Adam Mosseri, the head of Instagram, who told The Times’s “Hard Fork” podcast on Thursday that he does not expect Threads to become a destination for news or politics, arenas where Twitter has dominated the public discourse.
“I don’t want to lean into hard news at all. I don’t think there’s much that we can or should do to discourage it on Instagram or in Threads, but I don’t think we’ll do anything to encourage it,” Mr. Mosseri said.
The app, released on Wednesday, was presented as an alternative to Twitter, with which many users became disillusioned after it was purchased by Elon Musk in October.
Lawyers for Twitter threatened legal action against Meta, the company that owns Instagram, Facebook and Threads, accusing it of using trade secrets from former Twitter employees to build the new platform. Mr. Musk tweeted on Thursday, “Competition is fine, cheating is not.”
Mr. Trump has not been active on Twitter recently either, despite Mr. Musk’s lifting the ban that was put on Mr. Trump’s account after the Jan. 6, 2021, attack on the Capitol. The former president has instead kept his focus on Truth Social, the right-wing social network he launched in 2021.
But many of the G.O.P. candidates have begun making their pitches on Threads.
Nikki Haley, the former United Nations ambassador and former governor of South Carolina, made a video compilation of her campaign events her first post on the app. “Strong and proud. Not weak and woke,” she wrote on Thursday. “That is the America I see.”
Gov. Doug Burgum of North Dakota posted footage of his July 4 campaign appearances in New Hampshire, alongside a message on Wednesday that said he and his wife were “looking forward to continuing our time here.”
And Will Hurd, a former Texas congressman, made a fund-raising pitch to viewers on Wednesday.
“Welcome to Threads,” he said in a video posted on the app. “I’m looking forward to continuing the conversation here with you on the issues, my candidacy, where I’ll be and everything our campaign has going on.”
Francis Suarez, the Republican mayor of Miami, and Larry Elder, a conservative talk radio host, also shared their campaign pitches on the platform, as did two candidates running in the Democratic primary: Robert F. Kennedy Jr., a leading vaccine skeptic, and Marianne Williamson, a self-help author. Even Cornel West, a professor and progressive activist running as a third-party candidate, has posted.
Former Vice President Mike Pence and Vivek Ramaswamy, a tech entrepreneur, also established accounts — but have yet to post.
Among the holdouts: Former Gov. Asa Hutchinson of Arkansas and former Gov. Chris Christie of New Jersey, both Republicans.
The White House has not said whether Mr. Biden will join Threads. Andrew Bates, a White House spokesman, said on Thursday that the administration would “keep you all posted if we do.”