With this advertisement, Ogilvy and Mather position themselves as an expert in the field of advertising. They provide advice to customers, which they would receive nowhere else regarding message, procurement and placement. You can see they use their own advice in their advertisement. They use examples of being successful with customers, they use a corporate design similar to their other advertisements, do not use a spread, do not use 4 color, etc.
This is simply a well thought out advertisement, full of information positioning the company as an advertising expert. They do more that say “We’re Experts” as nearly every company does, they prove it.
I found this advertisement on http://www.infomarketingblog.com/david-ogilvy-on-long-copy/