https://techcrunch.com/2023/07/10/instagrams-threads-app-reaches-100-million-users-in-just-five-days/

Instagram’s text-based app Threads has achieved the mark of 100 million sign-ups in just five days. The Twitter rival was launched on June 6 (or June 5 in the Americas), according to a tracker.

Mark Zuckerberg noted on the first day that the app attracted 2 million sign-ups in two hours, 5 million sign-ups in four hours, and 10 million registered users in seven hours. The next morning, the CEO of Meta noted that more than 30 million people had signed up to try the new app.