Implicit v. Explicit

Implicit memory is information that a person retains without realizing that they have picked up something new.  It is unconsciously incorporated into their habits, how they respond emotionally or physically to situations.  It is information that can not be readily recalled.  It can only be triggered.  Memory and retention of things learned in this way is instinctual.  In some ways implicit memories interact with us similarly to the idea of déjà vu;  when presented with a stimulus, you might find it familiar but not understand why exactly you feel this way about this thing.  Your brain remembers something that you do not, and in a way that is too abstract for your conscious self to piece it together.  

Explicit memory is much less interesting.  Your memories here are retained as well as recalled through effort.  You must extend focus to a thing to gain concrete knowledge.

These two types of memory make me think of synesthesia, which is when your brain blends or confuses some of your sensory skills.  Different stimulus than expected connects with the individual, resulting in unusual associations.  Abstract ways to retain information, seem to be most beneficial.  Being able to make use of both types of memory is the best way to form patterns and reach conclusions along one's thought processes.