This could be a total tease or a hint at something else.

One of the Season Three episodes will focus in Felicity's backstory. Episode Title? "Oracle." #arrow #wbsdcc #dcsdcc — DC Comics (@DCComics) July 26, 2014

So they are tying the word or name Oracle to Felicity. In a way, that has been her role in Oliver's life. Just as Detective Lance is becoming Commissioner Gordon and Diggle is the more modern version of Alfred. So is this just a massive tease for the fans or with all the new heroes popping up, a central connection would make sense… and she would need a code name.