A year and a half ago, Threads was but a twinkle in Mark Zuckerberg’s eye.

Now, the rival to Elon Musk’s X has reached more than 175 million monthly active users, the Meta CEO announced on Wednesday.

As with any social network, and especially for Threads, monthly users only tell part of the growth story. It’s telling that, unlike Facebook, WhatsApp, and Instagram, Meta hasn’t shared daily user numbers yet. That omission suggests Threads is still getting a lot of flyby traffic from people who have yet to become regular users.

I’ve heard from Meta employees in recent months that much of the app’s growth is still coming from it being promoted inside Instagram. Both apps share the same account system, which isn’t expected to change.

Even still, 175 million monthly users for a one-year app is nothing to turn your nose up at, especially given Meta’s spotty track record of launching standalone app experiments over the years. Zuckerberg has been open to me and others that he thinks Threads has a real shot at being the company’s next billion-user app. To keep the growth story going, I’m told, Meta is focused on markets where it thinks there’s an opening to take more market share from X — Japan, for example.

For now, Threads is still a loss leader for Meta financially, though it can certainly afford to fund it indefinitely. Internally, I’m told execs are thinking about turning on ads in Threads sometime next year, though the exact plan is still up in the air. It’s easy to see how Threads could plug into Instagram’s existing ads system. And given Meta’s intentional decision to deprioritize politics and encourage lighthearted content, it could be a compelling place for advertisers looking for a more brand-safe alternative to X.

“It would be great if it gets really, really big, but I’m actually more interested in if it becomes culturally relevant and if it gets hundreds of millions of users,” the head of Instagram, Adam Mosseri, told me when Threads first launched. A year later, the app definitely has more progress to make on the cultural front. But the fact that it’s still growing means Meta has the runway to make that happen.