in 2012, as part of the settlement of another class-action lawsuit, Facebook agreed to allow users to opt in to its Sponsored Stories service, whith server advertisements that highlight products and businesses that your Facebook friends are using. Now, users can control and see which of their actions on Facebook generate advertisement that their friends will see. Sponsored Stories are one of the most effective forms of advertising on Facebook because they don't seem like advertisements at all to most users. Facebook had previously argued that users were giving "implied consent" every time thay clicked a Like button on a page. Users are now confronted with an opt-in notice that analysts speculate may cost Facebook ug to $103 million in advertising revenue