(photo by NYphotoblog.com)

In New York City, at the corner of 41st Street and Seventh Avenue, a billboard promoted the Weatherproof brand by showing one of its garments worn by US President Obama.

On the other side of the Atlantic, low-cost airline Ryanair made light of the then-upcoming wedding between French president Sarkozy and Carla Bruni. Thought bubbles show Bruni to be musing: “With Ryanair, all my family will be able to come to my wedding”.  Played straight, the ad comments on Bruni’s family, from Italy. As a joke, the ad kids about Sarkozy’s wish for a quiet ceremony, and about the considerable wealth of Bruni’s family.

Now rent-a-car company Sixt features the French presidential couple. There are no photos, only text. And although the ad exists on billboards in Germany, it is only found on the car rental company’s French web site. The ad shows a compact car and a tagline: “Do like Mrs. Bruni: opt for a small French model”.

I am less interested by the legality of these ads –do they violate a privacy interest? do they impermissibly convey state sponsorship?– than by their business interest. For these ads, which matters more: the actual campaign (which the advertiser controls) or the media thunderclap that they inevitably generate (which the advertiser does not control)? In either case, are these ads effective? Do they increase sales or build brand awareness? If so, is a political leader a better ambassador for a product than a sports star, movie actress, or other kind of celebrity?