Comparatively, ChatGPT took two months to reach 100 million users, while TikTok, the video-sharing app, achieved this milestone in nine months. Instagram itself took two and a half years to achieve the same level of user adoption after its launch in 2010.

Threads became available on Apple and Android app stores in 100 countries on Wednesday, although it is not accessible in Europe due to concerns from its parent company, Meta, regarding compliance with the European Union's data privacy legislation.

Twitter is estimated to have approximately 200 million regular users. However, the platform has faced recurrent technical issues since being acquired by Elon Musk last year, along with significant staff layoffs.

Elon Musk, who holds leadership positions at Tesla and SpaceX, has faced criticism from users for implementing charges for services that were previously free and reinstating banned right-wing accounts on Twitter. These actions have caused him to lose support from a significant number of users.

While there have been several emerging rivals to Twitter, most of them are niche platforms that lack the capability to grow on the required scale to challenge Twitter's dominance.
According to Quiver Quantitative, an online data service, the Threads app surpassed 100 million users at 07:00 GMT on Monday. However, other websites that track the number of badges received by Instagram users who have downloaded Threads estimated that the milestone had been reached earlier.

Elon Musk has made threats to sue Meta, the company that owns Instagram, Facebook, and WhatsApp, accusing them of stealing trade secrets and intellectual property. These claims have been denied by Meta.

Musk and Meta CEO Mark Zuckerberg are engaged in a rivalry, exchanging public jabs and even jokingly challenging each other to a cage fight.