Aside from procedural memory, Implicit Memory is the "new kid" on the block, in that not too much is known about it.
It appears we are capable having experiences where we learned something, and then lose all recollection of the experience.
The only traces that would be evident would be our responses on a test, which would be more correct than could be accounted for by random choice. This is compatible with a process of forgetting, we will talk about shortly, called trace inhibition.
Below in the notes is a web site which discusses implicit memory as it relates it to motor learning.
In the meantime, we will turn our attention to my favorite activity--forgetting.