People unconsciously ignore ads, not because they aren’t interested in the products or services that are being offered, but a natural instinct to focus on the material they’re reading and block out ‘distractions’. Remember: they’re on the web to look for information. That can be a particular song they want to download, an article on their favorite celebrity, or a chicken recipe they can cook for dinner. They’re concentrating on that issue, and their minds are quickly filtering out whatever seems to intrude on that search. That includes the background noise of the room they happen to be surfing in, and the visual noise on the web page.

Ads are said to be ‘visual noise’, and ironically, the larger (and more obvious) the ad, the more likely it’ll be ignored. That seems to go against all instincts of advertising