Researchers have accused tobacco companies of using YouTube to advertise their products, getting around a voluntary ban on cigarette advertising.
A new study published in the online journal Tobacco Control has called into question a number of "very professionally made" clips posted on the video sharing website.
Researchers from the University of Otago in New Zealand searched the site for references to the tobacco brands Marlboro, L&M, Benson and Hedges, Winston and Mild Seven.
Clips associated with the Marlboro brand were found to be the most watched, attracting an average of nearly 104,000 views each. One clip received two million views (probably more, now that the research has been made public...)
The researchers classified nearly three-quarters of the clips as 'pro'-tobacco, and less than four per cent as 'anti'.
Thirty-nine out of the 40 Marlboro videos posted featured the brand name in the title, and some of them used the iconic 'Marlboro Man' images of a man on a horse.
Other clips included archive material featuring celebrities films, sport and music.
The team points out the benefits to tobacco companies of this kind of free advertising, and the fact that that the companies, who hold the copyright to much of this material, have never tried to have it taken down.
A number of tobacco companies signed up to a voluntary agreement to restrict direct advertising of their products on the Internet.
"Tobacco companies stand to benefit greatly from the marketing potential of Web 2.0, without themselves being at significant risk of being implicated in violating any laws or advertising codes," said the team.
YouTube denies accepting any paid-for tobacco adverts.