Campaigners take aim at Facebook's privacy concerns

The group has set up an online petition against the move and has founded a Facebook group called 'Facebook, stop invading my privacy'. To date the group has over 7,000 members

"When you buy a book or movie online--or make a political contribution--do you want that information automatically shared with the world on Facebook?" the group says.

"Most people would call that a huge invasion of privacy. But recently, Facebook began doing just that. People across the country saw private purchases they made on other sites displayed on their Facebook News Feeds."

The furore kicked off when Facebook introduced its new Beacon advertising service. This is used in conjunction with around 40 ecommerce sites and posts up details of what users have bought on their Facebook news board.

If users want to keep their purchases secret then they can click on a Beacon box on the ecommerce site, but in many cases the box disappears after 20 seconds and consent is assumed to have been given.

So far Fandango, eBay and Sony are among the sites using the system.

"We encourage feedback from our users on new products," said Facebook in a statement.

"But in this case, the MoveOn.org-led group misrepresents how Facebook Beacon works. Beacon gives users an easy way to share relevant information from other sites with their friends on Facebook."

But this has cut little ice with MoveOn.org

"If Facebook's argument is that sharing private information with hundreds or thousands of someone's closest 'friends' is not the same as making that information 'public,' that shows how weak Facebook's argument is," said MoveOn.org spokesman Adam Green.

"Facebook users across the nation are outraged that the books, movies, and gifts they buy privately on other sites are being displayed publicly without permission--and it's time for Facebook to reverse this massive privacy breach."