"Sell more skating stuff to skateboard buyers" isn't the point of targeted advertising. A common misconception is that the targeting is related to what the customer wants, when it's really about creating ways sellers can target specific demographics. The goal isn't about selling some specific product; it's about hitting people at the specific times/situations they are likely to change their buying preferences.

I highly recommend reading this[1] article for a very good explanation about how this works.

[1] http://www.nytimes.com/2012/02/19/magazine/shopping-habits.h...