Charity Alcohol Concern has said in a report that young people are being targeted by alcohol companies via social networking sites such as Facebook and Twitter.
The charity examined all kinds of online marketing by the alcohol industry for the report, including branded websites with interactive games and competitions that are attractive to young people, and branded pages on websites including Facebook and YouTube.
It said websites set up by consumers themselves to back a particular brand are also very popular, and companies encourage viral marketing - a form of advertising targeted at those who are likely to pass on the message to others via social networking sites, emails, texts and online forums.
In the report ‘New Media, New Problem?’ said that 49% of children aged eight to 17 in the UK have set up their own profile on a social networking site.
Don Shenker, chief executive of Alcohol Concern, said: "The alcohol industry has very effectively taken advantage of internet technology as a means of promoting its products.
"Most of the leading drinks companies have a presence on Facebook or Twitter, plus their own websites which often contain content likely to be attractive to young people, such as games and videos, competitions and prizes.
"There's a real danger of children and young people being exposed to alcohol marketing on such sites, particularly given that age verification mechanisms are largely ineffective.
"This is especially worrying given that research shows that alcohol advertising and marketing have a significant impact on young people's decisions about alcohol.
"It's also increasingly common for young people to use sites like Facebook and YouTube to document their parties and nights out, posting details of their heavy drinking and discussing their favourite drinks.
"Many Facebook groups about drinks also mirror official drinks industry advertising and make use of official drinks logos. Much of this can be easily accessed by users of any age.
"The sharing of pro-drinking messages in this way fuels the normalisation of alcohol - the more people who are regularly exposed to images and descriptions of excessive consumption, the more normal and acceptable this behaviour appears."