Marketing doesn’t have to be subtle. I was recently sent a DVD from Lovefilm that contained a small complimentary bar of Green & Black’s chocolate (5p at cost price?). Being the greedy man I am, I knew this bar wouldn’t be enough once I’d started it, but even the thought of eating it got me salivating. Cursing the marketers involved for being so cunning, I immediately hastened to Sainsbury’s to stock up (in my defence, I bought some other stuff too).
This is clear and obvious - they know what they want you to do, you know what they want you to do. But it still works, because the product is good - the ‘ad’ just acts as a reminder at the right time (when I’m settling down for the evening). Seth Godin talks about this notion a lot - having a good product and marketing it in the right context. See this presentation he gave at Google for more.