In June 2018, Instagram hit a huge milestone: over 1 billion monthly active users. That’s double the number of users the platform had just two years before.

For now, it looks like growth on Instagram isn’t slowing down anytime soon. It helps that there are still many people not currently on the platform. Only 37% of U.S. adults use Instagram, according to 2019 Pew Research. To put that into perspective, 69% of adults use Facebook.

Instagram’s audience still skews a bit younger: 75% of 18- to 24-year-olds use Instagram as do ~60% of 25- to 29-year-olds. But only 8% of U.S. adults over 65 use Instagram. Facebook, comparatively, is used by 46% of American adults over the age of 65.

In the coming years, Instagram’s user base will likely diversify, and the good news is that once adults make it to Instagram, they spend a lot of time there. Those on Android phones spent 53 minutes a day on Instagram, a mere five minutes less than they spent on Facebook, according to SimilarWeb data from June 2018.

Because of its engaged, growing audience, marketers have gone all in on Instagram — especially with the countless woes they encountered on Facebook. 90% of marketers use Instagram to promote their products, according to a new report by Social Media Today. Plus, most (65%) find Instagram extremely or very important to their overall social media marketing.

Many forget, though, that Facebook owns Instagram. Facebook bought Instagram in April 2012 for $1 billion when Instagram had 30 million users and zero revenue.

A little more than a year later, Instagram introduced its first ads. Now, the majority of businesses (52%) advertise on Instagram. Companies are starting to rely on Instagram marketing the same way they used to rely on Facebook

But a new report from Trust Insights warns that marketers may need to gear up for a battle they know too well already: dwindling organic reach.

In early May, the average number of engagements on brand posts (namely likes) began declining. By the end of the month, engagements were down 18% compared to early in 2019. Fashion influencers, too, saw engagement on their posts fall — a whopping 44%.

This could be the result of nothing more than increased competition. Users are following more people and brands, so they engage with fewer posts.

But the story feels too similar to the one that marketers have just gone through on Facebook. They grow their audiences for free and count on the platform as a key part of their marketing strategy. Then, poof!

Their organic reach starts dropping, then goes into freefall. Finally, they must pay for sponsored posts or ad campaigns to maintain past levels of reach and engagement.

Is that what’s going to happen on Instagram in the long term?

For now, we’ll have to wait and see. But if you can, plan to distribute more of your social media advertising budget on Instagram in the latter half of 2019. Also, invest more in creating Instagram Stories! The above stats are specifically for the Instagram feed, and, for now, Instagram Stories still appear to be a haven.