For Knock Knock, a new stand-alone app, Humin tackled the problem of exchanging contacts in two ways. First, they made the interaction simpler: you don’t have to open the app and establish a connection before sharing. In fact only one person has to open the app. Secondly, the contact sharing options include more than just basic info like your phone number, email, and address. You can also share your Facebook, LinkedIn, Instagram and other social profiles as well.