Knock twice for friendship with this app
 

Say you've just met someone at a party. It turns out you guys go to the same school, hang out at the same coffee shops and are both really into John Steinbeck. Now it's time for you to part ways and you want to keep in touch, but it seems a little...

http://www.engadget.com/2015/08/19/k...cid%3Drss_semi