An easter egg often refers to a hidden area or feature that is usually trigger by something obscure enough that it could not be found by trial and error or by accident (like the Silver/Larian armour upgrade area). In this case, it is also includes references to books, other games, etc. that were deliberately put in the game, and areas/quests that were taken out of the game, which you are not suppose to be able to get to.
There is nothing to do with most easter eggs, they are just there to be discovered. An exception;
Larian/Silver armour-screenie-spoilerEASTEREGGS and RUNE manuscripts
