Facebook (FB) - Get Report has launched its fair share of Snapchat clones over the last several months, each one aimed at eroding the singular appeal of the popular ephemeral messaging app.

Facebook's latest copycat attempt, announced on Tuesday, allows users to send disappearing photos and videos via Instagram Direct, the platform's private messaging feature. Similar to Snapchat, the photos and videos can only be replayed once, and the sender will be notified if the viewer screenshots an image. Before Tuesday, this feature was largely unique to Snapchat, as Facebook's other Snapchat-like tools (Facebook Stories, Messenger Day, WhatsApp Status and, of course, Instagram Stories) could only be sent to a users' entire friend group, and not single accounts.

The move appeared to send shares of Snapchat parent company Snap (SNAP) - Get Report down 1.3% on Tuesday afternoon. Similarly, the stock also took a downward tumble earlier this month when Facebook launched the Stories feature on its core platform.

Both features do little to quiet concerns that Facebook is luring users away from Snap. Snap has been adding fewer new users to its platform in the past several months (five million new users were added in the fourth quarter of 2016 vs. 15 million in the third quarter), and Instagram Stories is widely considered to be the reason for the deceleration. Snap, meanwhile, blamed the slowdown on technical errors in the roll-out of new products, according to its S1 filing.

For its part, Instagram pointed to its growing user base as the reason for why it launched the new messaging features on Instagram Direct.

"Since our last update in November 2016, the number of people using Direct has grown from 300 million to 375 million," Instagram wrote in a blog post. "We want to make Direct the best place to have fun, visual conversations with your friends."

While Snap has seen its user growth sputter, Instagram added 100 million users over the last six months, bringing its total monthly active user count to 600 million. And its number of daily active users (DAUs) grew to 160 million in the fourth quarter.

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DAU growth will be the key metric on analysts' minds as Snap prepares to file its first financial results as a public company in late April or early May. Despite being divided on many things (such as Snap's high-flying valuation), Wall Street's bulls and bears have nearly all agreed that Facebook will continue to serve as a significant threat to Snap unless CEO Evan Spiegel can continue to innovate.

"Given the relative size and balance sheet strength of Snapchat's peers such as Facebook, competition has to be weighed seriously," said BTIG Research analyst Rich Greenfield, who last week initiated coverage of the stock with a Neutral rating. "Instagram Stories reinvigorated content sharing on Instagram (and Facebook clearly hopes it will do the same for Facebook with the launch of Facebook Stories) and may have given users less of a reason to try Snapchat, especially when all of their legacy connections were on Instagram."

BTIG was one of the 26 underwriting firms for Snap's IPO.

Snapchat has had some resiliency due to its overwhelming popularity among teens -- a factor that has helped it maintain a spot as one of the most heavily downloaded app for iOS and Android, Greenfield noted. Snapchat's Bitmoji app, which allows users to create personalized emojis, is currently the most-downloaded app in the U.S.

Additionally, Snapchat users open the app an average of 18 times per day, spending about 25 minutes per day on the platform. The average Facebook user spends about 50 minutes per day there, but that usage time has been close to plateauing recently.

"Once you are addicted and your connections are addicted to using Snapchat as your primary means of communicating, it is really hard to imagine leaving," Greenfield explained. "Sure, you can now post Stories to Facebook, Instagram and Whatsapp, but if you are getting inundated daily with Snaps from your Snapchat connections, you are going to keep using Snapchat."