PALO ALTO: After a couple of uncomfortable weeks under the glare of disgruntled 'friends', online social network Facebook has apologised for the way it launched its new advertising system.

Facebook founder Mark Zuckerberg (pictured) acknowledged a lot of "mistakes" had been made in debuting Beacon, which allows members to see what other users in their circle have purchased on partner websites.

Facebook claimed the marketing feeds would help users keep friends better informed about their interests, while also serving as "trusted referrals" to help drive more sales to the sites using the Beacon system.

However, it was met with uproar among many tens of thousands of users who felt their privacy was being invaded and that an opt-out option was not visible enough on screen.

As a result of the furore, Facebook has now changed Beacon from opt-out to opt-in. In addition, it can be switched off completely.

In a statement posted on the Facebook blog, Zuckerberg says: "We simply did a bad job with this release, and I apologise for it. I'm not proud of the way we've handled this situation and I know we can do better."

Data sourced from Financial Times online; additional content by WARC staff