Okay, I know product ads can be terrible. Any medium that offers a forum for the McDonald's chicken man or Carrot Top has forfeited the right to be taken seriously. You half expect these ads to be joined by an extortion letter: "Buy our products or we'll keep running these spots over and over."And has anyone in the ad business mastered basic grammar? "KFC is celebrating their 50th anniversary," I was informed recently by someone who clearly couldn't decide whether Kentucky Fried Chicken is singular or plural, and so opted to make it both in the course of a single sentence. But institutional advertising is worse. Take the recent campaign on behalf of the New York Stock Exchange, which includes both print and TV ads. The 30-second spot shows a parade of people - presumably some concerned ordinary investors - saying they expect honesty and integrity. The implied message is that shareholders can trust companies listed on the NYSE, but at no point does the ad explain why. There's no mention of new rules that might compel hitherto dishonest corporations to tell the truth, of any significant change in policies since several companies - NYSE companies among them - were caught lying and cheating. That can be forgiven, perhaps, in a short TV spot, but it's inexplicable in an equally content-free 16-page insert that ran in several major business titles. Then there are the new BP ads. Some are pretty good. The "person in the street" interviews, which depict ordinary consumers sharing advice on good corporate citizenship, are effective and sometimes funny. But some of the outdoor ads show what happens when a good PR program falls into the hands of an ad agency. One billboard touts the company's investment in alternative fuels: "Solar, natural gas, wind, hydrogen. And, oh yes, oil." That makes it sound as if environmentally friendly energy sources already make up the lion's share of BP's activities, when the reality is that more than 90% of BP's revenues still come from good old-fashioned petroleum. What's sad is that BP is actually doing a great job in terms of environmental and social policy. It is light years ahead of most of its competitors - unlike ExxonMobil, for example, it acknowledges the industry's role in global warming. It could tell its story in a straightforward manner, explaining the progress it has made and acknowledging it still has far to go. Instead, it allowed a copywriter, who probably thought he'd come up with a neat tagline, to overstate its progress. As such, it comes off looking like another big company blowing its own horn. Corporate ads are a vital tool in the PR arsenal. But they must be done with PR's substantive mindset, not advertising's affinity for the cute and catchy.