A discussion of recent work on time-dependent transport in mesoscopic
structures is presented. The discussion emphasizes the use of time-dependent
transport to gain information on the charge distribution and its collective
dynamics. We discuss the RC-time of mesoscopic capacitors, the dynamic
conductance of quantum point contacts and dynamic weak localization effects in
chaotic cavities. We review work on adiabatic quantum pumping and
photon-assisted transport, and conclude with a list which demonstrates the wide
range of problems which are of interest