Targeted advertising doesn't work; I booked an hotel online last year and over the next couple of months the only advertisements I saw were ones for that same hotel that I'd already booked! It was completely pointless....
Mind I never, ever, click on an ad banner or window on any website; when I want to make a purchase I do a search, compare prices and decide on a supplier. No amount of advertising is going to make me, suddenly, decide I might want to buy something if I'm not actively looking to do so..