Why do we give things names?  It's obvious right?  We give things names in order to identify them.  When children are born they're given names usually by their parents.  The naming is the first step in creating their identity separate from all others.  As one's personality develops some people will even at some point receive a nickname to further reflect what they represent.  But, what is a nickname?  First regarded as an "eke-name" meaning an additional name, which later became "neke name" due to an incorrect word division mixing noun with indefinite article, and by the Middle English era nickname meant a known variant.
It seems like everyone and everything has a nickname.  Nicknames can be good and bad, a good nickname can do one wonders, yet a bad one such as one given by a school bully can stick and negatively effect somebody their entire life.  We don't only label other human beings with nicknames, we give everything a nickname e.g. lollipops may be referred to as "lollies" or "suckers".  In cases such as this it seems that we assign nicknames because they are shorter and therefore more efficient than the original name.
Moreover, whether nicknames are providing a more expressive name to a person or making language more efficient I think nicknames are usually a good thing.

It was in 1939 when the world first met Batman in Detective Comics #27.  Batman, Bruce Wayne who as a young child witnessed the murders of both of his parents and feels responsible and dedicates his life to the service of justice.  Wayne doesn't do this by becoming a lawyer, judge, or police officer, no because it's fiction and a comic book instead he funds his alter ego, Batman, a superhero who utilizes technology opposed to powers to clean up the streets of Gotham.  I'm sure everything above is old news, everybody and their mother has general knowledge about Batman, but why does everybody know about Batman?  How did Batman go from a character featured in a comic book in 1939 to a character almost a brand known globally.
Just as Batman the character evolved, Batman as a pop culture icon evolved.  Since his inception in 1939 Batman has stayed relevant hardly ever fading.  Today, Batman whether it be in comics, movies, video games, on T-shirts, clocks, wallpaper, socks, you name and it has a Batman variety all of these things together make Batman a profit generating machine.
Batman is just one example of fiction or story that becomes a brand.  The same is true about Superman, Spider-man, Captain America, and almost every superhero they go from appearing in comics o appearing on everything from t-shirts to bow ties.  And, its just not comic book characters the same applies for characters and such from novels for example everybody knows who Harry Potter and Bilbo Baggins both characters from books(Harry Potter books, The Hobbit, The Lord of the Rings Trilogy).  The same thing can occur with popular TV shows and movies such as Star Trek and Star Wars.
This phenomenon when literature, movies and TV, all of which are encompassed by story inspire other literature, movies, TV, and even video games and go from a story to a brand is an incredible thing. I feel as though this speaks to society's infatuation with story that something as simple as a character can inspire books, movies, TV shows, clothing etc.