Instead of the classic "give us your e-mail to notify you" and then just launch for the entire world, they adopted a "waiting line" concept: people who signed up first will get the app first. This rewards early adopters but also allows for "bragging rights" as the app shows your number in the "line" and how many people are in front and behind you.
The result today is people filling the social networks with screenshots like the one below, showing how long the line is and if they are lucky (to be ahead) or unlucky (to have to wait a lot). And of course the tech press has something "exciting" to write about :)
One could say it's the digital equivalent of #Apple 's lines on product launches. It remains to be seen if other start-ups will copy this idea… :)