What is a Banner Ad?
A banner ad is a particular form of advertising on the Internet. It is usually a medium-sized display ad with some text written in the advertisement. These advertisements are embedded in a web page, and their main intention is to direct traffic to the advertiser’s web page once a visitor clicks on the advertisement. Most 
The significance of a banner ad is the fact that it created the quick development of Internet paid advertising. Using standardized formatting, pricing, and ad operations, the banner advertisements allowed for absolutely any web page to sell advertising space and for the advertisers to be able to track how their ad is doing. This method of advertising influenced visitors of one media channel to visit an entirely different media channel, which is far different from the previous advertising in magazines and newspapers.
Advantages & Disadvantages of a Banner Ad
Advantages

Easily Created – Animated and static banner ads can be created quite easily in free or low-cost software. When creating a banner ad, it helps to have a little bit of marketing and design knowledge.
Simplistic – The nature of banner ads is to have very little complexity. These particular advertisements are fairly easy to create and understand.
Draws Attention – A banner ad is a relatively large block of content which makes them more desirable to be clicked on by visitors to the website. Typically these ads are approximately 300×250 in size.
Disadvantages
Ads Can Be Blocked – Viewers can use software or turn off scripting to block advertisements.
Ads Can Be Ignored – Ads that are placed in traditional advertising spots on a website can be ignored because the viewers are aware they are ads.
Limited in Ad Space – A banner ad is limited in the amount of information it can convey to viewers. There are rules to govern the text to image ratio and how much content can be included in each ad.
Banner ads have their limitations, but the advantages far outweigh the disadvantages. A banner ad is a great way for businesses to start advertising their product or service, especially if your business is based predominantly on content you can display in images.