eHealth is changing the way we conduct public health surveillance and conceptualize processes of behavior change. It also is catalyzing a transformation of health care by promoting new tools for personalized monitoring and intervention and creating new models for health care delivery. The exciting prospects for eHealth need to be considered in the context of ongoing challenges in bringing eHealth up to scale, optimizing the efficiency of monitoring and evaluating just-in-time intervention effectiveness, and addressing ethical concerns related to eHealth monitoring and application in clinical practice. Addressing these challenges will bring us closer to realizing the goals of improving our understanding of alcohol-related behaviors and preventing and treating alcohol use disorders