All these privacy flaps have not diminished advertiser interest. Facebook serves ads on each user's home page and on the sidebars of user profiles. In addition to an image and headline from the advertiser, Facebook ads include the names of any user's friends who have clicked on a button indicating they like the brand or ad. A Nielsen Co. study found that including information about individuals a person knows in an ad boosted recall of the ad by 68 percent and doubled awareness of a brand's message. to determine what ads to serve to particular people, Facebook abstracts profile information into keywords, and advertisers match ads to those keywords. No individual data is shared with any advertiser.