The Threads app launched by Instagram as a rival to Twitter has signed up more than 100 million users in less than five days, data tracking websites said on Monday, smashing the record of AI tool ChatGPT for fastest-growing consumer app.
While ChatGPT took two months to hit the 100 million user mark and video-sharing app TikTok took nine months, Instagram itself took two and a half years to reach that mark after its 2010 launch.
Threads went live on Apple and Android app stores in 100 countries on Wednesday and Thursday, though it is not available in Europe because parent company Meta is unsure how to navigate the European Union's data privacy legislation.
Twitter is thought to have around 200 million regular users but it has suffered repeated technical failures since Tesla tycoon Elon Musk bought the platform last year and sacked thousands of staff.
Musk, also the boss of SpaceX, has alienated many users by introducing charges for previously free services and allowing banned right-wing accounts back on the platform.
Several rivals have emerged but most are niche platforms without the capacity to grow at the necessary scale to dethrone Twitter.
Threads is finding it easier because it is linked to Instagram, which has more than one billion regular users.
Online data service Quiver Quantitative reported that the app passed 100 million users at 0700 GMT on Monday.
Other websites using a count of the "badges" received by Instagram users who have downloaded Threads reckoned the mark had passed earlier.
But Europe's legislation around data privacy is giving Meta a severe headache.
The firm already faces regular fines for breaching the EU's data privacy regime (GDPR).
Now the forthcoming Digital Markets Act explicitly bans firms like Meta -- which also owns Facebook and WhatsApp -- from combining data across its platforms.
Its business model revolves around sucking up personal data to use for targeted ads and Threads accounts are linked to Instagram accounts.
In his first public reaction to Threads, the EU's industry commissioner Thierry Breton told French radio Franceinfo that Meta was right to try to make sure its apps conformed with the law.
"Taking a little time to do so seems to me to be probably good policy," he said, adding that there were plenty of solutions.
Meanwhile, Musk has threatened to sue Meta for stealing trade secrets and intellectual property, claims denied by the company.
The billionaire tycoon is also locked in a personal and increasingly juvenile rivalry with Meta chief Mark Zuckerberg.
The two men have been bickering for years, but things have become heated since it became clear Meta intended to compete with Twitter.
Last month, the two men called each other out for a cage fight, and when launching Threads, Zuckerberg tweeted for the first time in a decade.
He posted a popular meme of two Spider-Men looking at each other, taken as a reference to the similarity between Threads and Twitter.
On Monday, Musk took his beef with Zuckerberg to a new level, proposing that the two men engage in a "literal" penis-measuring contest.