because the people whos ads are on the banner pay them to put it on their site .

no they are not

Web banner ads vary in sizes. It depends on what you wanting. but the standard banner ad is 468 X 60 for a full size banner. Different sizes costs different amounts of money and this size is a great eye catcher.

A person can find a Google Banner Ads Guide on the Google Ads Help Center website. The Google Ads Help Center provides comprehensive resources, including step-by-step guides, tutorials, and best practices for creating and managing banner ads. Additionally, Google offers various educational resources, such as the Google Ads Academy, which provides courses and certifications related to advertising on Google's platforms. These resources can help individuals learn about the different ad formats, design guidelines, targeting options, and optimization strategies specifically related to banner ads on Google.

One might find the presence of banner ads annoying while visiting websites, if the banner ad keeps flashing. The time needed to load a page could be affected by banner ads as well.