According to the link, 
"Smack Cam" is when people (typically douchey bros or bitchy mean girls) smack unsuspecting victims and then post their stinging faces and shocked screams on Vine.

So. Um. Yeah. Something I have learned is that percentage wise....there appear to be more douche bags per capita than not.
And before someone argues that so many of them are a joke...
Maybe I am getting old and maybe I am no longer in possession of a sense of humor but I don't get how stuff like this is funny.
*sigh*
Sometimes I question whether or not I am really from this planet.