Abstract: Since the dawn of the Internet era, researchers, policy-makers and the general public have questioned how new technology is influencing our psychological well-being. This talk will review research I’ve done with students and collaborators over the past 18 years to cast light on this question. Our earliest work in the 1990s indicated that more Internet use, independent of type, predicted increases in depression and declines in other measures of well-being. However, later research demonstrates that whom one communicates with online and the nature of the communication are the important factors, not Internet use per se. In Facebook, for example, receiving targeted, composed communication from strong ties predicts improvements in well-being, while viewing wide-audience broadcasts, receiving one-click feedback, and receiving composed communication from weak ties does not. In online health support groups, it is messages exchanged in public that predict improvements in well-being, while private message exchanges predict declines.