Table 1

Application feature matrix

Target variable	Application feature	Levels
t	Expanded content (quit guides) ▸ A single generic quit guide supplemented by 9 additional topic-specific quit guides ▸ ‘Crave button’ that when pushed randomly displays a humorous video from a content library Proactive contact (app requests) ▸ Facebook requests: small icon appears on bookmark with flyover messages ▸ App notifications: user receives a notification when friends achieve specific cessation milestones ▸ Email: direct email on installation to the participant reminding them to come back	On: has all quit guides, all crave content, has proactive app notifications, and gets an email on installation Off: has one quit guide, limited crave content, no proactive app notifications and no email on installation
β-passive (βp)	Passive diffusion (sharing) ▸ Content (quit guides, crave content, check-ins, badges, money/life saved) can be shared on a user's Timeline ▸ Badges earned and quit status are automatically posted to a user's Timeline	On: content is sharable, Timeline posts are generated Off: content not sharable, Timeline posts not generated
β-active (βa)	Active diffusion (invites) ▸ During onboarding process, the user is prompted to identify and invite friends to either support them or quit with them ▸ A persistent clickable interface element is available to invite friends ▸ Users can post to a friend's Timeline using the ‘Cure’ and ‘Capture’ buttons (even if the friend has not installed) Social comparison (leaderboard) ▸ Compares individuals to others on various metrics. Table 1 compares individuals based on points earned in the app; Table 2 presents cumulative quitting metrics ($ saved, life saved) for the participants’ friends versus other participants’ local networks	On: user can invite friends, post to friends’ Timelines, and has both tabs of the leaderboard Off: user cannot invite friends, cannot post to friends’ Timelines through the app, and only has the individual tab of leaderboard
Z	Version for non-smoker supporters ▸ Non-smokers can install the application ▸ Original quit guide tailored non-smokers; access to all other quit guides ▸ Daily check-ins providing content on how to help a friend stay smoke-free ▸ Otherwise identical experience to smokers	On: smokers can have non-smoker supporters use the app Off: non-smoker supporters cannot use app (can install, but once declared non-smoker the app has no functionality)