Instagram has a new follower.

Meet Vero, a photo-sharing social media app that has suddenly exploded in popularity, gaining an estimated 500,000 users in just a few days, according to one report. As of Tuesday, it was the no. 1 most popular free app (in terms of new downloads) in Apple’s App Store — but just one week ago, it wasn’t even listed in the store’s top 1,500 apps. It is now closing in on one million users, a representative for Vero told Moneyish.

While it’s not clear exactly why this app, which has been around since 2015, is suddenly so hot, it might have to do with people’s frustrations around Instagram’s slew of ads and non-chronological ordering of news feed posts. Indeed, Vero, which was founded by billionaire businessman Ayman Hariri, promises a “true social” experience — namely, a rejection of the ads and algorithm that have changed the user experience on Instagram significantly in recent years.

Given all the interest around it, what makes Vero special? Alpana Deshmukh, a social media strategist and Instagram influencer who analyzed Vero for Moneyish, believes users are enjoying Vero’s ad- and algorithm-free nature, enabling you to share images without sponsored posts clogging up your feed or images appearing out of order.

And Nicolee Drake, a photographer who runs the @cucinadigitale Instagram account that commands more than 519,000 followers, praised the app’s cropping feature and integration with Apple Music. The feature allows you to share your favorite songs on Vero and let your friends listen to them right then and there, which is something Instagram doesn’t.

Plus, the app is currently free, though once it hits one million users (which the company says will be soon), it will begin charging new users for access to the service.

Still, Vero has a long way before it becomes a real rival to Insta, experts say.

“The functionality [of Vero] will take some getting used to; it’s a little bit clunky,” Deshmukh said. And Drake told Moneyish that Vero gave her a remarkable 20 error messages saying it had defaulted, preventing her from posting anything. That complaint was echoed by many others on other social media networks.

“The big question is, for influencers, what’s the objective to migrate here? Is Vero for sharing work within a personal network and keeping it social? If so, it would seem to serve that purpose,” Deshmukh added. It might be challenging for ordinary users to add a new social platform into their existing mix, she noted, although brands might have the bandwidth to shoulder the burden for marketing purposes.

What’s more, Drake wasn’t sold on the Google Plus-style feature that allows you to “categorize” your friends — namely, Vero’s function that lets you put your contacts in groups like Close Friends, Friends, and Acquaintances, to distinguish which of your followers can see your posts. It might be intended to keep some of your more personal photos private, but it makes the photo-sharing experience more arduous.

“If I’m putting out something on social, it’s probably just going to everyone. I wouldn’t keep track of it if my friends were close friends or acquaintances,” Drake said. “If I wanted to send someone something without everyone seeing it, I would send it to them privately [on iMessage or WhatsApp].”

Ultimately, Deshmukh and Drake don’t foresee the app really threatening Instagram’s dominance.

“Given the hype that’s happening, maybe it has potential,” Drake concluded. “We’ll see what happens. It may get a little bit of a burst, but as far as staying power… I haven’t seen anything that replaces Instagram yet.”