Barclaycard and The National Lottery have ceased advertising on Amazon's Internet Movie Database after their ads were placed next to listings for adult movie titles.

A range of other major brands, including mobile provider 3, HP, Motorola, Hilton Hotels, Citroën and Vauxhall, advertise across the entire site, but have yet to pull or modify their advertising campaigns.

Barclaycard stated that it is currently reviewing the situation and may reinstate its adverts soon.

"The Internet Movie Database seeks to list all the movies which have ever been made, including adult ones, but by no stretch of the imagination could it be described as a porn site," said a Barclaycard spokesman.

"As company policy, we seek to advertise only on reputable websites and temporarily removed our adverts from this site while we carried out a full investigation and spoke to the website."

The move follows recent action by advertisers on social networking site Facebook, when Vodafone and several other companies pulled advertising from the site after appearing next to profiles that violated company policies.

Facebook has since created an option allowing advertisers to blacklist content types with which they do not wish to be associated.

This raises questions about the future of advertising campaigns on sites that rely on user-generated content as marketers have little or no control over the type of content their ads will appear alongside.

Alex Ricketts, marketing services manager at the Incorporated Society of British Advertisers, a representative body for over 400 UK advertisers, told vnunet.com that Facebook is "leading the way forward".

Ricketts explained that brand image is very important in online advertising and that advertisers do not want to stifle the content that user generated sites put up.

"But they do need to be wary of brand damage through association with content that they may consider questionable," he added.

Ricketts maintained that it is a question of talking to the advertisers to make sure that proper measures are in place to minimise the exposure of brands to content they do not wish to be associated with, and that suitable processes are in place to remove ads if necessary.