Intermittency and other correlation phenomena in high energy collisions

We discuss the phenomenology of multiplicity fluctuations in small phase space cells ('intermittency') in connection with correlation functions and negative binomial fits. Whereas soft collisions show smooth, roughly energy independent short-range rapidity correlations, strong short-range correlations are expected to build up in e+e- annihilation with increasing energy and should become visible at LEP energies. We address the question to what extent present data can be explained by jet models and propose further tests. An anomalous collective effect is observed in nucleus-nucleus collisions which deserves further verification. (orig.)