  We consider a quiver structure on the set of quandle colorings of an oriented
knot or link diagram. This structure contains a wealth of knot and link
invariants and provides a categorification of the quandle counting invariant in
the most literal sense, i.e., giving the set of quandle colorings the structure
of a small category which is unchanged by Reidemeister moves. We derive some
new enhancements of the counting invariant from this quiver structure and show
that the enhancements are proper with explicit examples.
