Facebook, the social networking site, on Wednesday apologised for "mistakes" made in the roll-out of a controversial new advertising system and said it would offer users the ability to opt out of the service altogether.
In a message posted on Wednesday on Facebook's website, Mark Zuckerberg, its 23-year-old founder, said it had "made a lot of mistakes" in building its new Beacon technology, which sends messages when a Facebook user makes purchases on outside websites.
"But we've made even more with how we've hand-led them," Mr Zuckerberg said. "We simply did a bad job with this release, and I apologise for it."
Beacon has proved the most controversial of several new money-making technologies launched by the social network site last month. Facebook has come under pressure to perfect a revenue model after a recent Microsoft investment valued the company at $15bn.
Facebook made changes to Beacon last week after more than 50,000 users signed a petition demanding that the company not broadcast information about users' activity on other websites without their explicit permission.
The service now requires users to opt in to sharing messages over Beacon. Previously, a message would be broadcast to a user's friends automatically unless the user elected, within a certain amount of time, not to broadcast it. Mr Zuckerberg said Facebook would further tighten Beacon's privacy controls by allowing users to opt out of the service altogether.
The changes followed reports that advertising partners had also begun to voice doubts about the service, amid concerns that users could find it too intrusive.
Facebook's retreat marks the second time it has been forced to make changes to a new technology because of privacy concerns. Last year, users protested after it introduced "News Feed", which allowed users to keep track of their friends' actions on the site.
"We were excited about Beacon because we believe a lot of information people want to share isn't on Facebook, and if we found the right balance, Beacon would give people an easy and controlled way to share more of that information with their friends," Mr Zuckerberg wrote. "But we missed the right balance."