The proposed randomized controlled evaluation (N=960) of the Tweet2Quit intervention will biochemically verify abstinence out to 6-months follow-up and will test the personalized benefit for women of a women-only versus co-ed Tweet2Quit group. In a 3-arm design, the investigators will compare: 1) usual care, 2) Tweet2Quit-coed, and 3) Tweet2Quit-Women only.