Guy pranks his roommate with gradually increasing the personalization of facebook ads targeted only to his roommate.
One of the ads said "Trouble swallowing pills? Does it seem ironic that swallowing swords is easy and then small pills make you gag?" Given that the roommate is a sword swallower who gags on his vitamins, this ad prompted him to write on his facebook wall that he had just seen the "most targeted ad in the history of ad targeting."
Article goes on to explain that micro targeting can be highly effective, especially for a high priced B-to-B product.