  The properties of QCD vacuum and the confinement of quarks and gluons
certainly influence the multiparticle production processes. Some
phenomenological attempts of the consideration of related collective effects
and the possibilities of their experimental detection are briefly discussed in
this review. We consider in particular the correlation characteristics of pion
systems, statistical and hydrodynamical analogies, the problem of phase
transition from a quark-gluon plasma to a multipion state and the possible
modifications of the evolution of the quark-gluon jets. The presentation is
somewhat simplified and could be interesting for those only entering the field.
