(MeSH) 1 Adolescent 1 Adult 1 Aged 1 Attitude to Health 1 Female 1 Humans 1 Internet 1 Internet, classification Male 1 Middle Aged 1 Observational study 1 Online Social Networking 1 Peer Group 1 Smoking 1 Smoking Cessation 1 Social Networking 1 Tobacco Use Cessation Devices 1 Tobacco Use Disorder 1 Tobacco products/utilization 1 United States 1 Young Adult 1 adolescent 1 adult 1 aged 1 article 1 attitude to health 1 controlled study 1 female 1 follow up 1