Users must explicitly opt out of being included in “Social Ads”. For those who are not familiar with this concept, picture your profile mug in a sidebar ad suggesting you heartily endorse this event or product.

In the Social Ads tab, change Appearance in Social Ads to No one.

I’m really very surprised about the lack of “Hey! WTF?” that this feature has gotten, especially after the Beacon debacle and other Facebook criticisms.