The bit of game theory they actively present is Seinfeld&#x27;s &quot;Don&#x27;t Break the Chain&quot; technique. Snapchat marks and elevates contacts you individually snap at at least once a day, moving those contacts into more-and-more personally named categories (&quot;close friend&quot;, &quot;best friends&quot;, etc).<p>That bit is right in your face and rewards you for increased use.