The leading factors that determine the frictional response at the nanoscale were the main topics of debate at the recent Trends in Nanotribology conference, held at the International Centre for Theoretical Physics, Trieste, on 19-23 October 2009. Oded Ben-David, Roland Bennewitz, and Oleg Braun studied the tribological properties of large ensembles of asperities. Merlijn van Spengen studied the frictional response of microelectromechanical systems; and Bernd Gotsmann from IBM Zurich investigated wear at the nano-and mesoscales under dry and wet sliding conditions. Andre Schirmeisen from Germany presented the results of experiments with antimony particles on graphite that showed two distinct types of motion under ultrahigh-vacuum conditions. Consiglio Nazionale delle Ricerche, presented at the conference that oscillations of the normal load can lead to a transition from a state of high-friction stick-slip dynamics to a low-friction, smoothly sliding one.