60 Million Photos Are Disappearing Daily On Snapchat, A $70 Million App Built By Stanford Frat Brothers

If you ask college or high school students what apps they have on their cell phones, they'll unanimously say, "Facebook, Instagram and Snapchat."

The latter is a startup that was founded in May 2011 by Evan Spiegel, 22, and Bobby Murphy, 24. The pair met at Stanford University where they were fraternity brothers. Snapchat lets users take and send mobile photos to friends and draw or type messages on top of the photos.

The receiver can only view the photo message for a few seconds. After that, the image disappears and neither the viewer nor the sender can ever see it again.

The disappearing photo app is becoming a new, visual way to send a text message and The New York Times says 60 million photos are being shared over Snapchat daily. That's about one-tenth of Facebook's volume. About 3.4 million people used the app in December according to Nielsen, more than double Snapchat's November traffic.

The founders say SnapChat, which they describe as "a digital version of passing notes in class," is an appealing alternative to social networks like Facebook where everything is stored and shared on the web forever.

“It became clear how awful social media is,” Spiegel tells The New York Times. “There is real value in sharing moments that don’t live forever.”

The Venice Beach, California startup recently received $13.5 million from investors which valued the company at about $70 million. The lead investor in the deal, Benchmark Capital's Mitch Lasky, first heard about SnapChat from his 16-year-old daughter who used it in the same context as Twitter, Instagram and Facebook.

So, what is Snapchat, and how do you use it? Here's a walk-through of the app.