Indeed, product appearances on screen do not always come about through monetary deals struck between studios and brands, frequent as those arrangements may be. But Chet Fenster, of the media agency MEC Entertainment, says that "the audience has gotten to a point where they assume that everything they see is placement"—regardless of whether or not it's been paid for. And why shouldn't they? According to the most recent branded entertainment marketing forecast from research firm PQ Media, paid placement spending increased in the double digits during the last decade, and is now up to as much as $3.61 billion, if not more.

Hence the impression of at least one fan, who tweeted, "Without giving anything away, Purell was my favourite product placement in The Girl With The Dragon Tattoo."

The practice of showcasing consumer brands in films began as an informal barter system, dating as far back as 1896, when a representative for the Lever brothers (now Unilever), got two cases of Sunlight soap into a Lumière film. Those sorts of arrangements—a cereal box on screen in exchange for breakfasts in the studio cafeteria—continued in Hollywood, and still do, as prop masters and costume designers seek out supplies at minimal or no cost. But as an industry, product placement really took off in the '80s, with the notable appearance of Hershey's Reese's Pieces in E.T. The candy lured the alien out of his hiding place, and sales rose 65 percent after the movie's release.

E.T. came out in 1982, during a period when product-placement spending in the U.S. was rising dramatically, from $190 million in 1974 to $512 million in 1985, by PQ Media's count. Today, a dedicated team at Norm Marshall & Associates—one of the most prominent names in branded entertainment marketing—sift through more than 600 hundred scripts annually in search of placement opportunities. Where there's a sneaker to be worn or a beer to be sipped, the firm get clients "exposure in an organically favorable way for the brand," says NMA President Mark Owens, who has been in the business for two decades. Some deals are paid, others are trade; "more fees do exchange hands in film than in television," he noted. In general, "brands have a lot more control now than they did before."

At the highest level, companies "tend to insist on a great deal of artistic control, and in some cases will even collaborate on the screenwriting process," says Mark Crispin Miller, a professor of Media, Culture, and Communication at New York University. Brands not only want to see that their products appear desirable, but also that audiences are most effectively allured.

In 2003, media marketing consultant Erwin Ephron penned a now oft-cited Mediaweek article, "The Paradox of Product Placement," in which the titular conundrum is defined: "If you notice, it's bad. But if you don't notice, it's worthless." More recently, a study published in the Journal of Advertising comparing the effectiveness of overt versus subtle product placements found that viewers responded more positively when a brand's visibility was less prominent and less frequent. As the paper concluded, "Slapping one's brand on the big screen in a haphazard manner will yield disdain, not engaged consumers."