The above mentioned app is called The Faces of Facebook and it's created by mobile and web designer Natalia Rojas. When viewing the page you can see the number of people currently on the screen (the number keeps changing as more and more people create new accounts on facebook).
With a simple click of the mouse, tha app zooms on the area you clicked and reveals the picture of the pesron you clicked on and the profile pictures of others registering before and after that person. So, being chronologically organized, it is really interesting to find out who are the first people that joined the service (of course Mark Zuckerberg and the other co-founders of facebook are in the first places).
What about you? Well, click the ballon shaped icon on the upper right of the page next to the information icon to connect your account with the app. As always, you will be prompted to let the application access your profile info and your friend's list. Immediately, you receive a message about who is the first one of your friends (and what is his/her positon) that joined the popular social network and what is your place on the image as well.
Don't hesitate to use this app, as it's creator claims that it doesn't break any Facebook's privacy rule because it doesn't store any of the information displayed.
Comment below and have fun with The Faces of Facebook app.
