Advertisements are made for the purpose of encouraging consumers to buy products. Companies would not spend millions of dollars every year on advertising campaigns if they didn't believe that the ads would attract buyers.
Some ads, however, are simply annoying. I'm not necessarily referring to the ads' content (which is a related, but separate matter), but just the fact that the ads get IN YOUR FACE. For example, you're looking at a website and an annoying pop up appears to hawk some product, and getting rid of the pop up is easier said than done. Conversely, you want to watch a DVD, but you can't get to the content without having to first sit through ten minutes of non-skippable ads.
In those cases, do you actually make a point of NOT buying the company's product just as small way of protesting or "getting back" at the company in question?