The Snapchat founder compared content found on Instagram to that of short video-sharing platform TikTok, which has exploded in popularity among American teens.
Chinese-owned TikTok's "talent-based content is often more interesting than status-based content," he said at the Digital Life Design Conference in Munich on Sunday, speaking about Instagram. In response to whether TikTok will overtake Instagram, he said "it's possible."
Spiegel's Snapchat has more in common with TikTok than Facebook, which has managed to constrain the growth of Snapchat for years by copying its most defining features. With the 2016 release of Stories, a clone of a Snapchat feature with the same name, Facebook successfully drew users away from the then quickly-growing Snapchat. Across all of Facebook's properties, the feature now accounts for more than 500 million daily users, according to the company.
Facebook has attempted to similarly mimic TikTok, with the 2018 roll out of Lasso, a nearly identical app to TikTok. However, TikTok has shown few signs of slowing down.
"I love TikTok," Spiegel said on stage Sunday. "I'm a big fan."
Despite Facebook's attempts to copy some of TikTok's features, TikTok crossed the 1 billion downloads milestone early last year, according to data from third-party analytics site SensorTower, and it was the second most-downloaded app of 2019 globally.
Downloads, however, is only one indicator of the success of a platform. While Instagram boasts more than 1 billion monthly active users globally, third-party market research firm App Annie says TikTok has about 625 million monthly active users around the world.
Snapchat has not reported its number of monthly active users recently, but in October the company reported 210 million daily active users.
Even as Instagram stands high above TikTok, the app's meteoric rise in the U.S. has shown cracks in Facebook's dominance, and CEO Mark Zuckerberg is noticing. Zuckerberg has criticized TikTok over allegations of censorship on behalf of the Chinese government. TikTok, in the mean time, has begun poaching employees from Facebook and other tech darlings.
When Facebook reports its fourth-quarter earnings on Jan. 29, the company will release more current data on user growth across its properties.
-- CNBC's Sal Rodriguez contributed to this report