Very tiny answer to a tiny part of what you said above here

Pretty much everybody uses language to communicate what 'group' they're part of in some way.
Groups/subcultures/communities whatever you want to call it, have different words used frequently, such as your Tumblr users spewing 'literally' all over the place.
I'm not arguing for either position here, but I guess the benefit could be seen as a way of expressing where or to what you identify yourself.. loosely.