I'll bet you've visited a site only to be plagued by one, two, three or even more popup windows appearing to annoy you. Some poorly designed sites even pop up those same windows each time you visit a new page, making simple navigation a horrifying experience.
Some webmasters believe in popup advertisements. They believe that their sales or signups (newsletters) are substantially higher when they use popups. And, guess what, they are often correct. Sites do get good responses from popup advertisements. People do look at them and do respond to offers, forms and ads.
However, I, like many surfers, find popup advertisements unacceptable and cease to visit sites which use them heavily. I will put up with an occasional pop up window, but immediately close it without reading - for same reason I delete spam messages: I will not encourage their use by responding to them.
Pop-under windows, things that slide across screen and pictures that jump out at me will cause me to immediately leave site and more than likely I will never be back. I especially despise those exit window "services". A horrible invention, intended to deceive surfers and siphon traffic from legitimate sites. Of course, programs like Gator deserve immediate deletion as are run by scummiest of advertisers.
What kind of advertising do I respond to? I prefer a well-written article reviewing a product or service with a link to supplier or order screen, or a side-bar that I can read, or even a small graphic. I want information, I want to know WHY I should look at a product or service.
But most of all, I want a reference to that product or service. A more-or-less trusted source saying, "yes, this is worth looking at". That's best kind of advertising by far.
To illustrate how advertising on internet often works, imagine walking down street lined with a bunch of shops. Some shops have very nice window displays which show off products very well. These are stores which I would tend to visit as I can see exactly what they sell. The best of these stores have knowledgeable employees who know all about their products along with good signage which explains various facts (for example, coupons with recipes scattered throughout produce section). Their advertising would consist of flyers which described products, perhaps a newsletter and reviews by knowledgeable, respected people.