Researchers at the University of Illinois at Chicago found that tweets on e-cigarettes - battery-powered vaporisers that simulate tobacco smoking by producing an aerosol - often link to commercial websites promoting e-cig use.
While advertising for conventional cigarettes has long been prohibited in the US, e-cigarettes are advertised routinely in traditional media (print, television and radio) and social media, researchers said.
Jidong Huang, senior research scientist at UIC's Institute for Health Research and Policy and lead author of the study collected tweets and metadata related to e-cigarettes during a two month period in 2012.
Using novel statistical methodology and carefully chosen keywords, Huang and team captured more than 70,000 tweets related to e-cigs.
Among those 70,000 tweets, nearly 90 per cent were commercial tweets and only 10 per cent were 'organic', or individual consumer opinions.
Fully 94 per cent of the commercial tweets included a website link, while only 11 per cent of the organic tweets did.
Of the commercial tweets, 11 per cent mentioned quitting smoking, and more than one-third offered coupons or discounts to purchase e-cig products.
Although only 11 per cent of commercial tweets referenced smoking cessation, the absolute number is significant, Huang said, if considered over longer timeframes than the two months of the study.
"If kids or youth search for 'vaping pen' or 'e-cig' on Twitter, they will get links to commercial sites where they can purchase these items," said Huang.
Unlike Facebook and some other platforms where one can set privacy controls, all information on Twitter is accessible to anyone.
Previous research has demonstrated rapid growth in use and awareness of e-cigarettes among adults and youth in recent years.
However, there is limited evidence related to the products' long-term health impact, efficacy in smoking cessation - or role as a 'gateway' to other tobacco products.
The study did not look at who was exposed to the messages, but it is known that Twitter users are primarily young adults (30 per cent ages 18-29) and African American (27 per cent) or Latino (28 per cent), researchers said.
"Given the substantial youth presence on social media, the marketing of e-cigarettes on those platforms may entice non-smokers - youth in particular - to experiment with and initiate e-cigarette use," researchers said in the journal Tobacco Control.