Facebook Beacon

Beacon formed part of Facebook's advertisement system that sent data from external websites to Facebook, for the purpose of allowing targeted advertisements and allowing users to share their activities with their friends. Beacon would report to Facebook on its members' activities on third-party sites that also participate with Beacon. These activities would be published to users' news feed. This would occur even when users were not connected to Facebook and would happen without the knowledge of the Facebook user. One of the main concerns was that Beacon did not give the user the option to block the information from being sent to Facebook. Beacon was launched on November 6, 2007 with 44 partner websites. The controversial service, which became the target of a class-action lawsuit, was shut down in September 2009. Mark Zuckerberg, CEO of Facebook, characterized Beacon on the Facebook Blog in November 2011 as a "mistake". Although Beacon was unsuccessful, it did pave the way for Facebook Connect, which has become widely popular.

Beacon created considerable controversy soon after it was launched, due to privacy concerns. On November 20, 2007, civic action group MoveOn.org created a Facebook group and online petition demanding that Facebook not publish their activity from other websites without explicit permission from the user. In fewer than ten days, this group gained 50,000 members. After the class-action lawsuit, Lane v. Facebook, Inc., Beacon was changed to require that any actions transmitted to the website would have to be approved by the Facebook user before being published. On November 29, 2007, Stefan Berteau, a security researcher for Computer Associates, published a note on his tests of the Beacon system. He found that data was still being collected and sent to Facebook despite users' opt-outs and not being logged into Facebook at the time. This revelation was in direct contradiction to the statements made by Chamath Palihapitiya, Facebook's vice president of marketing and operations, in an interview with The New York Times published the same day:

Q. If I buy tickets on Fandango, and decline to publish the purchase to my friends on Facebook, does Facebook still receive the information about my purchase?
A. "Absolutely not. One of the things we are still trying to do is dispel a lot of misinformation that is being propagated unnecessarily."

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Wikipedia