  The relevance of higher order cumulants of conserved charges for the analysis
of freeze-out and critical conditions in heavy ion collisions at LHC and RHIC
is discussed. Using properties of $O(4)$ scaling functions, the generic
structure of these higher cumulants at vanishing baryon chemical potential is
discussed. Chiral model calculations are then used to study their properties at
non-zero baryon chemical potential. It is argued that the rapid variation of
sixth and higher order cumulants at the phase boundary may be used to explore
the QCD phase diagram in experiment. Moreover, results for the Polyakov loop
susceptibilities in SU(3) lattice gauge theory as well as in (2+1) flavor
lattice QCD are discussed. An analysis of the ratios of susceptibilities
indicates that the deconfinement transition is reflected in characteristic
modifications of these ratios.
