A LANDMARK ruling that Facebook is an advertising medium - and not just a way to communicate - will force companies to vet comments posted by the public to ensure they are not sexist, racist or factually inaccurate.
In a move that could change the nature of the social networking site forever, companies could be fined or publicly shamed for the comments that appear on their Facebook ''brand'' pages.
Last month the advertising industry watchdog issued a judgment in which it said comments made by ''fans'' of a vodka brand's Facebook page were ads and must therefore comply with industry self-regulatory codes and therefore consumer protection laws.
A media lawyer is warning that the Advertising Standards Board's ruling on Smirnoff's Facebook page will put the onus back on companies to be more vigilant about the nature of the comments people are posting to their company pages.
Large advertisers such as Qantas, Telstra and Coles are increasingly reliant on their Facebook pages to get consumers to ''like'' them and get free referrals to their network of friends.
John Swinson, a partner at law firm King & Wood Mallesons, said the board's ruling "turned people's opinions into statements of facts".
Mr Swinson said that if, for example, a member of the public posted a comment on Smirnoff's site that claimed it was the purest Russian vodka and would lead to success with the opposite sex and Smirnoff failed to remove it, the company could be liable on a number of counts.
"Smirnoff is Australian not Russian. So that is false. It may not be the purest so that could also be misleading.
''And to imply that you would have greater success with girls would contravene the advertising codes," said Mr Swinson.
In a note to clients, Mr Swinson warned that the standards that govern regular TV, radio or billboard advertising might now apply to third-party posts on Facebook pages.
And because the competition watchdog is cracking down on claims made by companies in social media - principally by people who are paid to do so - Mr Swinson warns that advertisers could end up in court.
Misleading and deceptive advertising is covered by Australian consumer law and each month the ad regulator publicly censures errant advertisers.
Although the Advertising Standards Board dismissed the original complaint about Smirnoff, which centred on sexism, under-age drinking and obscene language, it ruled industry codes applied not only to what a company was posting on its Facebook page but to the user-generated comments that followed.
The board's determination also cited a recent case of a health company, Allergy Pathway, which was fined for allowing misleading and deceptive "testimonials" to remain on its Facebook and Twitter pages.
The board's comments threatened to have "far-reaching ramifications" for social media, which thrived on people's ability to share information quickly, said a consultant, Thomas Tudehope.