And so the lesson is this: it doesn't really matter what you're selling; you just have to think about who is your customer, and what are the messages that are going to get them to change their behavior.
Et la leçon c'est : il n'importe pas vraiement ce que tu vend, tu dois seulement penser à qui est ton client, et ce qui sont les messages qui vont leur faire changer leur comportement.