One of the features of Snapchat that I thought was cool when the app first launched was the Snapcode. It made connecting with people on the service pretty frictionless. You could just scan a branded QR code to automatically follow a specific person. No typing, asking clarifying questions or anything, just scan and go!
I didn’t know until recently that Twitter has ripped off the same system so you can quickly create a Twitter QR code that will allow people to automatically follow you. Here is the Twitter help article showing you how to do it and a quick screencast from my iPhone showing you as well.