Ever since cave painting, people with something to say have invited the attention of those they might profit from. As for today's magazines, no one would be surprised to hear that a potential advertiser had been told about a forthcoming article or review coincidentally favorable to the advertiser's interests.
What does surprise many - and what has caused the American Society of Magazine Editors (ASME) to issue a statement of concern - is a reverse editor-advertiser relationship: Now some advertisers want "early warning" about scheduled articles so they can withhold ads if they find the articles too controversial or offensive. The danger is the powerful tail of advertising wagging the editorial dog. This was a worry of the ASME board, "that some advertisers may mistake an early warning as an open invitation to pressure the publisher or editor to alter, or even kill, the article in question."
Advertisers can obviously choose the editorial company they keep. They pick a given magazine with the kind of audience they want to reach. Such magazines will be less valuable if they lose credibility - and readers - by failing to be true to themselves.