  Properties of local Polyakov loops are studied in finite temperature lattice
QCD and SU(3) lattice gauge theory. We evaluate local Polyakov loops, identify
the closest center element for each loop and investigate cluster properties of
these center phases. For a suitable definition of the clusters we find that the
deconfinement transition of pure SU(3) gauge theory may be characterized by
percolation of the center clusters. For the case of full QCD cluster
observables show a behavior which seems to be compatible with a smooth
crossover type of transition.
