Inside Facebook's Eric Eldon got his hands on an email Facebook sent to advertisers, assuring them that "this change will not affect your advertising campaigns," in part because it's not clear many users will actually take advantage of the new, purportedly easier-to-use privacy settings:
Please note that this change will not affect your advertising campaigns and there is no action required on your part....
While a majority of our users love Facebook apps and Facebook-enhanced websites, some may prefer not to share their information outside of Facebook. Users can now opt out with just one click.
Maybe Facebook is saying very few users will take advantage of its new privacy settings, so there will be no impact on ad traffic. Or maybe the social network is simply as shifty and hard-to-pin down in its communications with advertisers as it is in its communication with users.