Arguably the strongest and most effective use of product placement came upon Hershey before production of the classic film E.T. When Spielberg had originally written the movie he had wanted E.T to mutter M&M’s but simply couldn’t reach an agreement for the rights for them. So as history was rewritten Reese’s Pieces had to be used, this placement boded very well for Hershey as sales skyrocketed for the candy and helped the brand increase market share. This is one of the most successful uses of product placement in movies (save for cigarette brands in early films).
The use of product placement in modern media is far more subtle than it was back then, whether it is certain car that someone gets into or a label on a can that is always facing a camera it almost appears subliminal these days, and certainly aren’t as memorable as E.T saying your brand of candy as he munches them down.