Meta’s Threads app looks set for an uphill climb if it’s ever to take the microblogging crown from Twitter, which is currently being rebranded as X.

Meta CEO Mark Zuckerberg recently told employees that despite its impressive start in early July when around 100 million people activated a Threads account in its first five days of availability, more than half of those users have stopped checking in.

The revelation came in a call to employees that was heard by Reuters.

“Obviously, if you have more than 100 million people sign up, ideally it would be awesome if all of them or even half of them stuck around,” Zuckerberg said in the call, adding: “We’re not there yet.”

The CEO didn’t seem too perturbed, however, describing the fall in user numbers as “normal” and saying that he believed Threads’ base will grow as the app adds new features, which could include a desktop version and the ability to search the platform’s content.

Threads got off to a flying start for two main reasons. First, there was a lot of buzz around the app just prior to launch. This created a high level of expectation among users of Twitter who’ve been unhappy with the way Elon Musk has been tampering with the platform since buying the company for $44 billion in October 2022.

And second, Threads has tight integration with Instagram — another Meta app with well over a billion users — making it easy for people to set up a Threads account, get followers, and find other accounts to follow.

Threads bore a striking resemblance to Twitter at launch, indeed, a lawyer acting on behalf of Musk’s business threatened to sue Meta for creating a “copycat” product. But at the start, Threads was pretty bare bones, lacking a number of features that you’d expect to see with such an app. Since then, however, its development team has been working to improve Threads’ usability. Just last week, for example, it added a Following feed that shows posts only from people you follow, offering users another option alongside the existing algorithmic feed.