Background Despite the internet's broad reach and potential to influence consumer behaviour, there has been little examination of the volume, characteristics, and target audience of online tobacco and e-cigarette advertisements.

Methods A full-service advertising firm was used to collect all online banner/video advertisements occurring in the USA and Canada between 1 April 2012 and 1 April 2013. The advertisement and associated meta-data on brand, date range observed, first market, and spend were downloaded and summarised. Characteristics and themes of advertisements, as well as topic area and target demographics of websites on which advertisements appeared, were also examined.

Results Over a 1-year period, almost $2 million were spent by the e-cigarette and tobacco industries on the placement of their online product advertisements in the USA and Canada. Most was spent promoting two brands: NJOY e-cigarettes and Swedish Snus. There was almost no advertising of cigarettes. About 30% of all advertisements mentioned a price promotion, discount coupon or price break. e-Cigarette advertisements were most likely to feature messages of harm reduction (38%) or use for cessation (21%). Certain brands advertised on websites that contained up to 35% of youth (<18 years) as their audience.

Conclusions Online banner/video advertising is a tactic used mainly to advertise e-cigarettes and cigars rather than cigarettes, some with unproven claims about benefits to health. Given the reach and accessibility of online advertising to vulnerable populations such as youth and the potential for health claims to be misinterpreted, online advertisements need to be closely monitored.