SAN FRANCISCO — “What’s going on here @tim_cook?” Elon Musk tweeted on Monday to Tim Cook, the chief executive of Apple, igniting a spat between the world’s richest man and the world’s most valuable public company.
In a series of tweets over 15 minutes, Mr. Musk, the new owner of Twitter, accused Apple of threatening to withhold Twitter from its App Store, a move that would limit some new users from downloading the app. The action would amount to censorship, Mr. Musk said. He added that Apple had also reduced its advertising spending on Twitter.
With the tweets, Mr. Musk set the stage for a power struggle with Mr. Cook, who holds immense influence over other tech companies through Apple’s dominance. Mr. Musk has a vested interest now in Apple’s clout because of his ownership of Twitter, which he bought last month for $44 billion and which is used by iPhone owners around the world. In one tweet, Mr. Musk implied he was ready for “war” with Apple.
A spokesman for Apple did not immediately respond to a request for comment.
Apple’s power over mobile apps begins with its App Store, a prime gateway where billions of iPhone users download Twitter, Facebook, Snapchat, games and all sorts of other software programs. Apple charges a 30 percent fee to developers to sell their software in the store, which has turned apps into a multibillion-dollar business for the Silicon Valley company and made it an arbiter of software distribution.
But that power has created a backlash among app developers, and Apple has faced growing pressure from regulators and politicians around the world over the App Store and its policies. Its App Store is the target of an antitrust investigation by the Justice Department. Last year, the Senate also introduced antitrust legislation aimed at fostering competition with both Apple’s and Google’s app stores.
With just a few changes, Apple can also affect mobile advertising. Last year, it made a series of tech changes to enhance people’s privacy with mobile apps. Those shifts made it harder for many apps to target advertising to users, rankling tech executives including Mark Zuckerberg, the chief executive of Meta, which owns Facebook and Instagram.
Apple also requires companies to create a “safe experience” for their apps to be listed in its App Store. In the past, Apple and Google have used their positions as the essential link between app developers and consumers to press for content moderation. After the Jan. 6 riot at the U.S. Capitol last year, Apple blocked the “free speech” social network Parler from appearing in its App Store until the service introduced guardrails to prevent calls for violence on the service.
“In my time at Twitter, representatives of the app stores regularly raised concerns about content available on our platform,” Yoel Roth, Twitter’s former head of trust and safety, wrote in an editorial in The New York Times this month. Mr. Roth said App Store reviewers had raised concerns about pornography and racial slurs on Twitter.