Ten million users signed up for Meta’s newly launched Threads app in its first seven hours, according to the company’s chief Mark Zuckerberg.
He pitched the app as a “friendly” rival to Twitter, which was bought by Elon Musk in October, last year.
Experts say Threads could attract Twitter users unhappy with recent changes to the platform.
Threads allows users to post up to 500 characters, and has many features similar to Twitter.
Earlier, Mr Zuckerberg said keeping the platform “friendly… will ultimately be the key to its success”.
But Mr Musk responded saying it is infinitely preferable to be attacked by strangers on Twitter, than indulge in the false happiness of Instagram.
When asked on Threads whether the app will be “bigger than Twitter”, Mr Zuckerberg responded saying it will take some time, but there should be a public conversations app used by over 1 billion people.
Competitors have criticised the amount of data the app might use.
This may include health, financial, and browsing data linked to users’ identities, according to the Apple App Store.
Some users have also expressed concern that it is not possible to delete your Threads profile without deleting the associated Instagram profile.
But the firm said deactivation will mean that a user’s Threads profile, posts and interactions with others’ posts will not be visible.
Users can download and delete Threads data by visiting their Instagram settings, Meta says.
Threads is now available to download in over 100 countries including the UK, but not yet in the EU because of regulatory concerns.