Rumors are swirling that Facebook is readying its own version of Snapchat, the massively popular new messaging app that lets you send pictures (and now video) to friends and have them self-destruct up to ten seconds later. Snapchat is only a year old, yet 50 million messages a day pass through its servers — so it’s no wonder Facebook is interested. If Snapchat continues doubling its numbers every couple months it could soon hit 300 million photo messages sent per day, which is close to the number of pics Facebook’s 1 billion users upload every 24 hours. As technically proficient as the social network’s engineers may be, its Snapchat clone (if there is one) has the deck stacked against it for one simple reason: Snapchat’s motto — its killer feature — is incontrovertibly at odds with Facebook’s.

Snapchat’s most important feature is that it’s private and ephemeral — the polar opposite of Facebook’s core features: tagged photos and the News Feed. It’s hard to find an interview with Mark Zuckerberg where he doesn’t speak about "openness," and how the world would be a better place if people shared more. Facebook has a tight grip on every picture or status you’ve ever posted — as evidenced by Timeline and its Activity Log feature. It also recently launched a feature that auto-uploads photos you’ve taken on your phone whenever you launch the Facebook app. Make no mistake — these features are tremendously powerful and useful, but they are the opposite of Snapchat: a place where people want their private data to be quickly destroyed. Even if the social network could replicate or improve on Snapchat’s self-destruct functionality, it would face an uphill battle convincing people Facebook is the right place to share embarrassing or illicit texts.

Facebook's Snapchat could face the same fate as Airtime, BuzzFeed's Matt Buchanan suggests, a technically superior product that fails to capture the mojo of the "killer feature" it's aping. Airtime was pitched informally as a beautiful, structured, and Facebook-integrated version of Chatroulette, which is an anonymous and global video chatting service that went viral back in 2010. But using Chatroulette felt safe, as strange as that sounds for an app that facilitated video chats with a random person from across the world. The site’s poor design and lack of structure was comforting. "No way," we think — "Chatroulette isn’t recording my videos or tracking me. It can’t even run a website!" Airtime stumbled and essentially hit rock bottom because it misunderstood what made Chatroulette so compelling. Airtime felt staged, scripted, and "verified," since you were talking to Facebook-connected users, which sucked the fun right out of the concept.

In the same vein, Snapchat is new and goofy enough that we trust it with our sexts, videos, and images of our contorted faces we want to send to friends. A Facebook app that lets you send "exploding time bomb" messages to friends would work quite well, I’m sure, but can’t possibly emulate the aura of privacy that surrounds Snapchat. Snapchat’s time bomb messaging platform is brilliant and novel, but it's not just this feature that makes it so successful. Snapchat’s real strength, like Instagram, is the loyal community it has created around a very focused use case. Instagram’s filters were recently ported to various apps like Flickr, Twitter, or Facebook, and Snapchat’s time bomb messages will be emulated too. Cloning a feature is easy, but it’s not the same thing as crafting a new medium and a loyal user base.

I’m not saying Snapchat is the "next big thing," or the next Instagram. I’m saying that Facebook cannot build a successful Snapchat clone — because that app would rely on the premise that users will share their most embarrassing or sexual pictures using it. One could hypothesize that privacy concerns are the reason Facebook's stellar cross-platform Messenger platform hasn't completely replaced texting. At least for now, people aren't going to share without second thoughts using any service with Facebook’s logo stamped on its forehead.