The aim was to better understand structural factors associated with uptake of automated tailored interventions for smoking cessation. In a prospective randomized controlled trial with interventions only offered, not mandated, participants were randomized based on the following: web-based expert system (QuitCoach); text messaging program (onQ); both as an integrated package; the choice of using either or both; or a control condition informed of a static website (not considered here). Participants were 3530 smokers or recent quitters recruited from two sources; those seeking smoking cessation information, mostly recruited over the phone, and a cold-contacted group recruited from an Internet panel. More participants (60.1%) initially accepted the intervention they had been offered than used it (42.5%). Uptake of each intervention differed substantially by both recruitment source and modality (phone or web). onQ was a little more popular overall, especially in the information seeker sample. Highest overall intervention uptake occurred in the choice condition. A web-based intervention is most attractive if the offer to use is made by web, whereas a phone-based intervention is more likely to be used if the offer is made over the phone. Providing automated interventions on multiple platforms allows for maximal choice and greatest overall use of some form of help.