A colleague pointed out about a crowdsourced phone directory app Truecaller that allows you to find name against a given phone number in any country. Some of us gathered near the colleague’s workstation and it was fun to input your and your friends number to see what (interesting) names are returned by the app.

This is how it works. Once you install the app on your phone, it takes your address book and stores it with itself. All users address book is then combined to return you the result.

But soon we all realized how this can seriously intrude your privacy without your knowledge and permission to share your number.

You can actually pay a small fees and request for contact information by name anywhere in the world!

In principle, building a telephone directory is not a bad idea. I also like the way crowding model is used to build information set that can help, for example, to identify calls from unknown numbers. However the app adds your name and number without your but someone else’s permission. Kinda scary.

What do you guys think?