Can you see web advertising?

datacharmer writes: "Can you actually see advertising? Some people are blind to ads. They filter off ads in their brain, leaving just an indistinct noise in the page, like an ink stain. This fact could be the side effect of indirect self training, triggered by continuous usage of the web. People using the web on a daily basis don't see the advertising anymore, or don't pay any attention to it. One wonders why the advertisers bother to use these techniques. And you? Do you see web advertising?"