Tech billionaires Mark Zuckerberg and Elon Musk have been joking about setting up a cage match. In the business world, the fight has already begun.
Less than 24 hours after Mr Zuckerberg launched his alternative to Twitter, Threads, it had already claimed some 30 million sign-ups - lending it credibility as a serious contender in the world of social media.
That's still a small fraction of the hundreds of millions of Twitter users.
But analysts think it's a sign that Mr Zuckerberg's Meta has a good shot at wooing some of its gigantic 3 billion-plus users on Facebook, Instagram and WhatsApp to the new offering - and bringing advertisers with them.