To better understand smokers' needs for quitting with a virtual coach, we conducted a study in which 671 smokers interacted with a text-based virtual coach in up to five conversational sessions spread over at least nine days. In each session, the virtual coach assigned people a new preparatory activity for quitting smoking or becoming more physically active, such as noting and ranking reasons for quitting smoking. Based on 1) people's experiences with their activities, 2) their barriers and motivators for doing their activities, 3) their characteristics (e.g., age, physical activity identity), 4) their views on interaction scenarios, and 5) findings from the literature, we found 14 main themes that describe user needs. These findings have now been published in the article “Users' needs for a digital smoking cessation application and how to address them: A mixed-methods study” in the journal PeerJ.