The advertising banners are what see with different images with text of companies on online web sites these days. online-bannerThey come in different sizes. So the company who's interested to market themselves would pay the publishers.
There are two major types of banners, static banners and dynamically-rotated banners. Static Banners do not change, they stay the same to every user, every page load. Dynamically-Rotated Banners can change for each user.
A dynamically-rotated banner is usually a more effective way of advertising, but it requires a program to work, most commonly a java script. With dynamic-rotation, you are able to advertise a different banner to each viewer, therefore you are able to have multiple advertisers, or, multiple banners for one advertiser, or any combination.
With a static banner, you can only have a single banner, and only a single advertiser for that page.