Before it was the world’s most popular messaging app, WhatsApp wasn’t even a messaging app. Founder Jan Koum simply thought it would be neat to open his address book and see status messages—at the gym, in a meeting—next to everyone’s names. He also knew no one wants to endure the rigamarole of creating a username and password, maintaining a buddy list, and joining yet another social network just to know what their friends are up to. So Koum let people log into WhatsApp using only a phone number. He also used the iPhone’s Address Book API to automatically scan your contacts to see who you knew who was already using the service.
Great growth-hacking, yes, but helping people find friends proved more of a side effect than anything. “I was just lazy and couldn’t remember my Skype password,” Koum says. “I kept having to get new usernames and start all over. I went through, like, three different accounts in the matter of a summer, and I was like, ‘Screw this.'” Looking back, though, he considers the decision central to WhatsApp’s massive success. “You look at the painful experience you’d have with some of the legacy messaging apps on a desktop, and the elegance and simplicity of SMS,” Koum says. “To us, it was just like, well, if SMS can do it, why shouldn’t we?”
WhatsApp was among the first apps to equate your account with your phone number. Now apps like Snapchat, Twitter, and Facebook Messenger do it too. Starting this fall, setting up your iPhone will be as easy as punching in your number. The supposedly super-secure way of logging into apps involves texting you a secret code to verify your identity. Phone numbers are killing the username, killing the password, and making it easier than ever to go wild online. So guard it with your life, because it is your life.
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