Last week, Meta’s new Twitter competitor, Threads, hit an astonishing metric in just seven hours: 10 million user signups. It took Twitter more than two years to reach that milestone. But it seems like that was just the warm-up act for Mark Zuckerberg’s latest social network. According to data compiled by Quiver Quantitative’s Threads Tracker, Threads has now crossed the 100 million users mark.

To put into perspective just how astonishing a feat that is, here is the time it took other social media platforms to hit the 100 million user marker, according to a 2019 report from The Motley Fool:

• Google+: 1 year and 2 months
• Instagram: 2 years and 4 months
• Myspace: 3 years
• Snapchat: 3 years and 8 months
• Facebook: 4 years and 6 months

A Twitter blog post from 2011 shows it took Twitter 5 years and 6 months to hit the 100 million mark. Threads did it in under 5 days. And sure, the 100 million milestone for those other social media networks came at a time when social media wasn’t as ubiquitous as today. But to give a more modern example, it took ChatGPT, the hottest platform of the past five years, two months to reach 100 million users, according to Reuters.

Given the rapid acceleration of Threads’ user base since its launch last Wednesday, it’s no wonder Elon Musk is hurling insults at Mark Zuckerberg. However, we’ll need to wait until at least early August to really see how Threads is doing. That’s when Meta will have the first concrete information on Threads’ monthly active users (MAUs). The MAU metric is the gold standard platforms use to track their success. MAUs are always lower than a platform’s total user base because some people sign up to a platform but never engage with it, or do so very rarely. (It’s unclear if Meta will break out Threads user data in future earnings reports, but it will clearly have to discuss the platform’s performance.)

According to data from Statista, Twitter in 2022 had 368.4 million MAUs worldwide. It’s unknown where that number stands since Musk took over. As a private company now, it does not reveal quarterly statistics. But if Threads’ users signups keep increasing, and a majority of those signups translate into MAU’s, then Musk is certain to start feeling the heat come the dog days of August.