A discussion of recent work on time-dependent transport inmesoscopic structures is presented. The discussion emphasizesthe use of time-dependent transport to gain information on thecharge distribution and its collective dynamics. We discussthe RC-time of mesoscopic capacitors, the dynamic conductanceof quantum point contacts and dynamic weak localizationeffects in chaotic cavities. We review work on adiabaticquantum pumping and photon-assisted transport, and concludewith a list which demonstrates the wide range of problemswhich are of interest.