Display ads have been the mainstay of online advertising since inception, and have continued to thrive despite the contrary by naysayers. Over the years display ads have evolved, and have grown in the number of formats and capabilities, not to mention adaptations for mobile devices. Some formats have done extremely well for themselves and continue to demand a premium in CPM, some have done well as a combination (like a side kick), while others have faded away in relevance. It would be interesting to chronicle the history or the evolution of these ads, but that would be covered in a future article.
In this article, let us look at some of the popular ad formats in relevance today across desktop and mobile devices along with their attributes and performance recommendations to help you get the most out of a display ad.
300x250 also known as the Medium Rectangle
This is one of the most popular display ad format available, which also means a larger share of the ad inventory from advertisers. Since this ad format has been around for a long time, most websites have used this format and have figured out a way to optimize for performance. As an advertiser you are most likely to push your ads to websites using this format and hence get more visibility and conversions. Similarly, as a publisher you are more likely to increase your earnings if you use the 300x250. This format tends to perform well if it is positioned in between content or towards the end of the article. This ad unit is versatile and also works well as a mobile ad-unit because of the width (<320 pixels).
336x280 also known as the Large Rectangle
This is a bigger version of the medium rectangle, and is as popular. Because of the size of the ad format and the relatively large area that it covers, it tends to perform slightly better than the medium rectangle. Google's ad serving also has a versatile version of the 336x280 that can accommodate a 300x250 to maximize performance of when a bigger sized version isn't available. However, the argument in the community is rife about its advantages over the 300x250.
728x90 also known as the the Leaderboard
This is a universal ad format that is supported by Google, Microsoft, Yahoo, IAB (interactive advertising bureau) and other ad networks. It tends to perform well when placed above the main content, or alongside the logo. Interestingly, leader board and medium rectangle are also the most paired appearing as a combination in over 40% of websites that I sampled.
300x600 also known as the Half Page
This format covers a larger real-estate of the page drawing more attention (better engagement) and can fetch better CTR. The 300x600 is one of the fastest growing sizes by impressions and is indicative of a trend where publishers are offering more visually impactful ad sizes that are preferred by brand advertisers. However, this format also comes at the cost of content or more ads since it takes up a lot of space.
160x600 also referred to as the Wide Skyscraper
The 160x600 was a popular ad format in the past and still retains a good % of the inventory. However, because of better performance and when available, publishers prefer the half page unit to this one.
970x250 also called the Billboard
This is a recent entrant into the repository of ad formats, but quickly gaining reputation as a top performer. As with any larger ad format, the engagement levels of this ad unit are high and works well for brand or exposure led campaigns.
320x100 also known as the Large Mobile Banner
This is an ad unit designed specifically for mobile devices. The 320x100 is a top performer and can be used as an alternative to its shorter cousin, the 320x50 or the 300x250.